WorldWideScience

Sample records for comparable fission power

  1. Comparative evaluation of solar, fission, fusion, and fossil energy resources. Part 2: Power from nuclear fission

    Science.gov (United States)

    Clement, J. D.

    1973-01-01

    Different types of nuclear fission reactors and fissionable materials are compared. Special emphasis is placed upon the environmental impact of such reactors. Graphs and charts comparing reactor facilities in the U. S. are presented.

  2. Status of fission power

    International Nuclear Information System (INIS)

    Levenson, M.

    1977-01-01

    Fission energy is reviewed from the viewpoints of technology, economics, politics, manufacturers, consumers, and foreign countries. Technically, the reactor program is operating and the light water reactor industry shows signs of maturing, although recent business has been disappointing. Marketing of gas-cooled reactors depends, not on technical, but economic and political issues. Liquid metal fast breeder reactors have been demonstrated worldwide, while the gas-cooled fast breeder remains an undemonstrated option. Nuclear plants, currently costing the same as coal plants with scrubbers, are the cheapest option for utilities because most of the cost is imbedded. The defeat of nuclear initiatives in seven states indicates that public feeling is not as anti-nuclear as opponents to nuclear power claim. The harshness of last winter demonstrated the advantages of a power source that is not so sensitive to the weather for reliable operation and transport, as well as low cost energy. Other nations are proceeding to build a nuclear capability, which the U.S. may jeopardize because of concerns about the fuel cycle, nuclear waste disposal, uranium reserves, and nuclear proliferation

  3. Lunar surface fission power supplies: Radiation issues

    International Nuclear Information System (INIS)

    Houts, M.G.; Lee, S.K.

    1994-01-01

    A lunar space fission power supply shield that uses a combination of lunar regolith and materials brought from earth may be optimal for early lunar outposts and bases. This type of shield can be designed such that the fission power supply does not have to be moved from its landing configuration, minimizing handling and required equipment on the lunar surface. Mechanisms for removing heat from the lunar regolith are built into the shield, and can be tested on earth. Regolith activation is greatly reduced compared with a shield that uses only regolith, and it is possible to keep the thermal conditions of the fission power supply close to these seen in free space. For a well designed shield, the additional mass required to be brought fro earth should be less than 1000 kg. Detailed radiation transport calculations confirm the feasibility of such a shield

  4. Lunar surface fission power supplies: Radiation issues

    International Nuclear Information System (INIS)

    Houts, M.G.; Lee, S.K.

    1994-01-01

    A lunar space fission power supply shield that uses a combination of lunar regolith and materials brought from earth may be optimal for early lunar outposts and bases. This type of shield can be designed such that the fission power supply does not have to be moved from its landing configuration, minimizing handling and required equipment on the lunar surface. Mechanisms for removing heat from the lunar regolith are built into the shield, and can be tested on earth. Regolith activation is greatly reduced compared with a shield that uses only regolith, and it is possible to keep the thermal conditions of the fission power supply close to those seen in free space. For a well designed shield, the additional mass required to be brought from earth should be less than 1,000 kg. Detailed radiation transport calculations confirm the feasibility of such a shield

  5. Options for Affordable Fission Surface Power Systems

    International Nuclear Information System (INIS)

    Houts, Mike; Gaddis, Steve; Porter, Ron; Van Dyke, Melissa; Martin, Jim; Godfroy, Tom; Bragg-Sitton, Shannon; Garber, Anne; Pearson, Boise

    2006-01-01

    Fission surface power systems could provide abundant power anywhere on the surface of the moon or Mars. Locations could include permanently shaded regions on the moon and high latitudes on Mars. To be fully utilized, however, fission surface power systems must be safe, have adequate performance, and be affordable. This paper discusses options for the design and development of such systems. (authors)

  6. The future of fission-electric power

    International Nuclear Information System (INIS)

    Morowski, J.V.

    1983-06-01

    Future worldwide electricity supply needs dictate the necessity of maintaining a sound capability for electricity and electric power generating facilities, including nuclear, as viable export commodities. A survey of fission-power plant types and the status of worldwide nuclear electric power illustrates the primary emphasis on LWR's and HWR's as two leading types in the export market. This survey examines the factors affecting the market prospects for the next five to fifteen years and provides a discussion on some possible improvements to current market circumstances. A comparative description is provided for some of the types of LWR and CANDU characteristics such as quantities, schedules, constructability factors, and equipment and system. Important factors in the selection process for future nuclear power plants are discussed. Some factors included are seismic design requirements; plant design description and possible site layout; plant protection, control and instrumentation; thermal cycle design and arrangement; and special construction and rigging requirements

  7. Fission Surface Power Technology Development Update

    Science.gov (United States)

    Palac, Donald T.; Mason, Lee S.; Houts, Michael G.; Harlow, Scott

    2011-01-01

    Power is a critical consideration in planning exploration of the surfaces of the Moon, Mars, and places beyond. Nuclear power is an important option, especially for locations in the solar system where sunlight is limited or environmental conditions are challenging (e.g., extreme cold, dust storms). NASA and the Department of Energy are maintaining the option for fission surface power for the Moon and Mars by developing and demonstrating technology for a fission surface power system. The Fission Surface Power Systems project has focused on subscale component and subsystem demonstrations to address the feasibility of a low-risk, low-cost approach to space nuclear power for surface missions. Laboratory demonstrations of the liquid metal pump, reactor control drum drive, power conversion, heat rejection, and power management and distribution technologies have validated that the fundamental characteristics and performance of these components and subsystems are consistent with a Fission Surface Power preliminary reference concept. In addition, subscale versions of a non-nuclear reactor simulator, using electric resistance heating in place of the reactor fuel, have been built and operated with liquid metal sodium-potassium and helium/xenon gas heat transfer loops, demonstrating the viability of establishing system-level performance and characteristics of fission surface power technologies without requiring a nuclear reactor. While some component and subsystem testing will continue through 2011 and beyond, the results to date provide sufficient confidence to proceed with system level technology readiness demonstration. To demonstrate the system level readiness of fission surface power in an operationally relevant environment (the primary goal of the Fission Surface Power Systems project), a full scale, 1/4 power Technology Demonstration Unit (TDU) is under development. The TDU will consist of a non-nuclear reactor simulator, a sodium-potassium heat transfer loop, a power

  8. Regulatory aspects of fusion power-lessons from fission plants

    International Nuclear Information System (INIS)

    Natalizio, A.; Brunnader, H.; Sood, S.K.

    1993-01-01

    Experience from fission reactors has shown the regulatory process for licensing a nuclear facility to be legalistic, lengthy, unpredictable, and costly. This experience also indicates that much of the regulatory debate is focused on safety margins, that is, the smaller the safety margins the bigger the regulatory debate and the greater the amount of proof required to satisfy the regulatory. Such experience suggests that caution and prudence guide the development of a regulatory regime for fusion reactors. Fusion has intrinsic safety and environmental advantages over fission, which should alleviate significantly, or even eliminate, the regulatory problems associated with fission. The absence of a criticality concern and the absence of fission products preclude a Chernobyl type accident from occurring in a fusion reactor. Although in a fusion reactor there are large inventories of radioactive products that can be mobilized, the total quantity is orders of magnitude smaller than in fission power reactors. The bulk of the radioactivity in a fusion reactor is either activation products in steel structures, or tritium fuel supplies safely stored in the form of a metal tritide in storage beds. The quantity of tritium that can be mobilized under accident conditions is much less than ten million curies. This compares very favorably with a fission product inventory greater than ten billion curies in a fission power reactor. Furthermore, in a fission reactor, all of the reactivity is contained in a steel vessel that is pressurized to about 150 atmospheres, whereas in a fusion reactor, the inventory of radioactive material is dispersed in different areas of the plant, such that it is improbable that a single event could give rise to the release of the entire inventory to the environment. With such significant intrinsic safety advantages there is no a priori need to make fusion requirements/regulations more demanding and more stringent than fission

  9. Fission Surface Power System Initial Concept Definition

    Science.gov (United States)

    2010-01-01

    Under the NASA Exploration Technology Development Program (ETDP) and in partnership with the Department of Energy (DOE), NASA has embarked on a project to develop Fission Surface Power (FSP) technology. The primary goals of the project are to 1) develop FSP concepts that meet expected surface power requirements at reasonable cost with added benefits over other options, 2) establish a hardwarebased technical foundation for FSP design concepts and reduce overall development risk, 3) reduce the cost uncertainties for FSP and establish greater credibility for flight system cost estimates, and 4) generate the key products to allow NASA decision-makers to consider FSP as a preferred option for flight development. The FSP project was initiated in 2006 as the Prometheus Program and the Jupiter Icy Moons Orbiter (JIMO) mission were phased-out. As a first step, NASA Headquarters commissioned the Affordable Fission Surface Power System Study to evaluate the potential for an affordable FSP development approach. With a cost-effective FSP strategy identified, the FSP team evaluated design options and selected a Preliminary Reference Concept to guide technology development. Since then, the FSP Preliminary Reference Concept has served as a point-of-departure for several NASA mission architecture studies examining the use of nuclear power and has provided the foundation for a series of "Pathfinder" hardware tests. The long-term technology goal is a Technology Demonstration Unit (TDU) integrated system test using full-scale components and a non-nuclear reactor simulator. The FSP team consists of Glenn Research Center (GRC), Marshall Space Flight Center (MSFC) and the DOE National Laboratories at Los Alamos (LANL), Idaho (INL), Oak Ridge (ORNL), and Sandia (SNL). The project is organized into two main elements: Concept Definition and Risk Reduction. Under Concept Definition, the team performs trade studies, develops analytical tools, and formulates system concepts. Under Risk

  10. Low Cost Radiator for Fission Power Thermal Control, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA Glenn Research Center (GRC) is developing fission power system technology for future space transportation and surface power applications. The early systems are...

  11. Low Cost Radiator for Fission Power Thermal Control, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA GRC is developing fission power system technology for future space transportation and surface power applications. The early systems are envisioned in the 10 to...

  12. Nuclear Power from Fission Reactors. An Introduction.

    Science.gov (United States)

    Department of Energy, Washington, DC. Technical Information Center.

    The purpose of this booklet is to provide a basic understanding of nuclear fission energy and different fission reaction concepts. Topics discussed are: energy use and production, current uses of fuels, oil and gas consumption, alternative energy sources, fossil fuel plants, nuclear plants, boiling water and pressurized water reactors, the light…

  13. Comparison of environmental impact of waste disposal from fusion, fission and coal-fired power plants

    Energy Technology Data Exchange (ETDEWEB)

    Frey, Bruno [Fichtner GmbH und Co. KG, Stuttgart (Germany)

    2011-08-15

    The radiotoxic hazard of waste from fusion power plants has been compared with that of fission power and radioactive trace elements in coal ash within some research programs such as SEAFP and SEIF. Within another program, in 2005 a Power Plant Conceptual Study (PPCS) has been finalized investigating 4 fusion power plant models A to D. In this paper, the radiotoxicity of model B is compared with a fission power plant, concentrating on the production of wastes. The hazard of the respective masses of enriched uranium before use in a fission power plant and coal ash of a power plant generating the same amount of electricity are used as benchmarks. It is evident that the development of ingestion and inhalation hazard of the PPCS model B is different from the results of earlier studies because of different assumptions on material impurities and other constraints. An important aspect is the presence of actinides in fusion power plant waste. (orig.)

  14. Reference reactor module for NASA's lunar surface fission power system

    International Nuclear Information System (INIS)

    Poston, David I.; Kapernick, Richard J.; Dixon, David D.; Werner, James; Qualls, Louis; Radel, Ross

    2009-01-01

    Surface fission power systems on the Moon and Mars may provide the first US application of fission reactor technology in space since 1965. The Affordable Fission Surface Power System (AFSPS) study was completed by NASA/DOE to determine the cost of a modest performance, low-technical risk surface power system. The AFSPS concept is now being further developed within the Fission Surface Power (FSP) Project, which is a near-term technology program to demonstrate system-level TRL-6 by 2013. This paper describes the reference FSP reactor module concept, which is designed to provide a net power of 40 kWe for 8 years on the lunar surface; note, the system has been designed with technologies that are fully compatible with a Martian surface application. The reactor concept uses stainless-steel based. UO 2 -fueled, pumped-NaK fission reactor coupled to free-piston Stirling converters. The reactor shielding approach utilizes both in-situ and launched shielding to keep the dose to astronauts much lower than the natural background radiation on the lunar surface. The ultimate goal of this work is to provide a 'workhorse' power system that NASA can utilize in near-term and future Lunar and Martian mission architectures, with the eventual capability to evolve to very high power, low mass systems, for either surface, deep space, and/or orbital missions.

  15. Antiproton Powered Gas Core Fission Rocket

    International Nuclear Information System (INIS)

    Kammash, Terry

    2005-01-01

    Extensive research in recent years has demonstrated that 'at rest' annihilation of antiprotons in the uranium isotope U238 leads to fission at nearly 100% efficiency. The resulting highly-ionizing, energetic fission fragments can heat a suitable medium to very high temperatures, making such a process particularly suitable for space propulsion applications. Such an ionized medium, which would serve as a propellant, can be confined by a magnetic field during the heating process, and subsequently ejected through a magnetic nozzle to generate thrust. The gasdynamic mirror (GDM) magnetic configuration is especially suited for this application since the underlying confinement principle is that the plasma be of such density and temperature as to make the ion-ion collision mean free path shorter than the plasma length. Under these conditions the plasma behaves like a fluid, and its escape from the system is analogous to the flow of a gas into vacuum from a vessel with a hole. For the system we propose we envisage radially injecting atomic or U238 plasma beam at a pre-determined position and axially pulsing an antiproton beam which upon interaction with the uranium target gives rise to near isotropic ejection of fission fragments with a total mass of 212 amu and total energy of about 160 MeV. These particles, along with the annihilation products (i.e. pions and muons) will heat the background U238 gas - inserted into the chamber just prior to the release of the antiproton - to one keV temperature. Preliminary analysis reveals that such a propulsion system can produce a specific impulse of about 3000 seconds at a thrust of about 50 kN. When applied to a round trip Mars mission, we find that such a journey can be accomplished in about 142 days with 2 days of thrusting and requiring only one gram of antiprotons to achieve it

  16. Fission gas release during power change by means of re-irradiation of spent fuel

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Jinichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    A full length rod irradiated at Tsuruga unit 1 was refabricated to short length rods, and rod inner pressure gauges were re-instrumented to the rods. Re-irradiation tests to study the fission gas release during power change were carried out by means of BOCA/OSF-1 facility at JMTR. In the tests, steady state operation at 40kW/m, power cycling and daily load follow operations between 20 and 40kW/m were conducted for the same high power holding time, and the rod inner pressure change during the tests was measured. The rod inner pressure increase was observed during power change, especially during power reduction. The rod inner pressure increase during a power cycling depended on the length of the high power operation just before the power cycling. The width of the rod inner pressure increase during a power cycling decreased gradually as the power cycling was repeated continuously. When steady state operation and power cycling were repeated at the power levels of 30, 35 and 40kW/m, the power cycling accelerated the fission gas release compared with the steady state operation. The fission gas release during power reduction is estimated to be the release from FP gas bubbles on the grain boundary caused by the thermal stress in the pellet during power reduction. (author)

  17. Evaluation of axial fission gas transport in power ramping experiments

    International Nuclear Information System (INIS)

    Kinoshita, Motoyasu

    1986-01-01

    The LINUS code calculates advective and diffusional transport of fission gas towards an upper plenum through the pellet-cladding gap. The basic equations were modified for analyzing a multi-component gas mixture in the gap and also for dealing with opening and/or closing of the gap, which induces additional axial gas flow. Analysis of the Petten ramp experiment shows that helium pressurization is effective in suppressing an ascending rate of fission gas concentration. After the maximum concentration is achieved through power ramping, the gas concentration could be described by a steady state analytical solution which does not depend on the filling gas pressure. (author)

  18. An assessment of fission product data for decay power calculation in fast reactors

    International Nuclear Information System (INIS)

    Sridharan, M.S.; Murthy, K.P.N.

    1987-01-01

    A review of our present capability at IGC, Kalpakkam to predict fission product decay power in fast reactors is presented. This is accomplished by comparing our summation calculations with the calculations of others and the reported experimental measurements. Our calculations are based on Chandy code developed at our Centre. The fission product data base of Chandy is essentially drawn from the yield data compiled by Crouch (1977) and the data on halflives etc. compiled by Tobias (1973). In general, we find good agreement amongst the different calculations (within ±5%) and our calculations also compare well with experimental measurements of AKIAMA et al and MURPHY et al

  19. Metrology for New Generation Nuclear Power Plants - MetroFission

    International Nuclear Information System (INIS)

    Johansson, Lena; Dinsdale, Alan; Keightley, John; Filtz, Jean-Remy; Hay, Bruno; DeFelice, Pierino; Sadli, Mohamed; Plompen, Arjan; Heyse, Jan; Pomme, Stefaan; Cassette, Philippe

    2013-06-01

    MetroFission project has been looking at solving metrological problems related to a new generation of NPPs. The proposed Gen. IV NPPs are designed to run safely, make efficient use of natural resources, minimize the waste and maintain proliferation resistance. In order to reach these goals, the reactor operation involves higher temperatures, high-energy neutron fluence, different types of fuel where the minor actinides are included etc. The work has focused on improved temperature measurements, investigation of thermal properties of advanced materials, determination of new and relevant nuclear data and development of measurement techniques for radionuclides suitable for Gen. IV NPPs. The improved temperature measurement for nuclear power plant applications includes the development of a new Fe-C fixed point. Robust, repeatable and versatile cells have been constructed and compared with success among the project participants and their melting temperatures have been determined. Methodology of self-validating thermocouples has proven efficient at several fixed point temperatures using different designs. A practical acoustic thermometer has been tested at 1000 deg. C with success thanks to the use of innovative signal processing methods. Mo/Nb thermocouples have been obtained with different sheath materials and tested with the aim to achieve for the first time a reference function determined with the best possible uncertainties. Following reviews of designs and technology proposed for fourth generation nuclear plants effort within this project, with regards to thermal properties of advanced materials for nuclear design, has concentrated on provision of thermodynamic data to support the development of the sodium cooled fast reactor. Data has been critically assessed to represent the potential interaction between the Na coolant and the nuclear fuel taken to be based on (U, Pu)O 2 but incorporating minor actinides such as Np and Am. Data for the fission products and

  20. Fission Surface Power Technology Demonstration Unit Test Results

    Science.gov (United States)

    Briggs, Maxwell H.; Gibson, Marc A.; Geng, Steven M.; Sanzi, James L.

    2016-01-01

    The Fission Surface Power (FSP) Technology Demonstration Unit (TDU) is a system-level demonstration of fission power technology intended for use on manned missions to Mars. The Baseline FSP systems consists of a 190 kWt UO2 fast-spectrum reactor cooled by a primary pumped liquid metal loop. This liquid metal loop transfers heat to two intermediate liquid metal loops designed to isolate fission products in the primary loop from the balance of plant. The intermediate liquid metal loops transfer heat to four Stirling Power Conversion Units (PCU), each of which produce 12 kWe (48 kW total) and reject waste heat to two pumped water loops, which transfer the waste heat to titanium-water heat pipe radiators. The FSP TDU simulates a single leg of the baseline FSP system using an electrically heater core simulator, a single liquid metal loop, a single PCU, and a pumped water loop which rejects the waste heat to a Facility Cooling System (FCS). When operated at the nominal operating conditions (modified for low liquid metal flow) during TDU testing the PCU produced 8.9 kW of power at an efficiency of 21.7 percent resulting in a net system power of 8.1 kW and a system level efficiency of 17.2 percent. The reduction in PCU power from levels seen during electrically heated testing is the result of insufficient heat transfer from the NaK heater head to the Stirling acceptor, which could not be tested at Sunpower prior to delivery to the NASA Glenn Research Center (GRC). The maximum PCU power of 10.4 kW was achieved at the maximum liquid metal temperature of 875 K, minimum water temperature of 350 K, 1.1 kg/s liquid metal flow, 0.39 kg/s water flow, and 15.0 mm amplitude at an efficiency of 23.3 percent. This resulted in a system net power of 9.7 kW and a system efficiency of 18.7 percent.

  1. The Power Makers' Challenge And the Need for Fission Energy

    CERN Document Server

    Nicholson, Martin

    2012-01-01

    The Power Makers - the producers of our electricity - must meet the demands of their customers while also addressing the threat of climate change. There are widely differing views about solutions to electricity generation in an emission constrained world. Some see the problem as relatively straight forward, requiring deep cuts in emissions now by improving energy efficiency, energy conservation and using only renewable resources. Many electricity industry engineers and scientists see the problem as being much more involved.   The Power Makers ’ Challenge: and the need for Fission Energy looks at why using only conventional renewable energy sources is not quite as simple as it seems. Following a general introduction to electricity and its distribution, the author quantifies the reductions needed in greenhouse gas emissions from the power sector in the face of ever increasing world demands for electricity. It provides some much needed background on the many energy sources available for producing electricity ...

  2. Application of Campbell's MSV method in monitoring of reactor's fission power

    International Nuclear Information System (INIS)

    Stankovic, S.J.; Vukcevic, M.; Loncar, B.; Vasic, A.; Osmokrovic, P.

    2003-01-01

    This paper presents some possibilities of Campbell's MSV (Mean Square Value) method in monitoring the reactor's fission power. Investigation of gamma discrimination compared to neutron component of signal along with change of variance and mean value the detector output signal for a specified range of reactor's fission power (10mW-22W) was carried out. The uncompensated ionization chamber for mixed n- gamma fields was used as detector element. Experimental measurements were performed using digitized MSV method, and obtained results were compared to those obtained by classical measuring chain. The final conclusion is that the order of discrimination in MSV signal processing is about fifty times larger than for classical measuring method (author)

  3. Effect of power change on fission gas release. Re-irradiation tests of spent fuel at JMTR

    International Nuclear Information System (INIS)

    Nakamura, Jinichi; Shimizu, Michio; Ishii, Tadahiko; Endo, Yasuichi; Ohwada, Isao; Nabeya, Hideaki; Uetsuka, Hiroshi

    1999-01-01

    A full length rod irradiated at Tsuruga unit 1 was refabricated to short length rods, and rod inner pressure gauges were re-instrumented to the rods. Re-irradiation tests to study the fission gas release during power change were carried out by means of BOCA/OSF-1 facility at the JMTR. In the tests, steady state operation at 40 kW/m and power cycling operations between 20 and 40 kW/m were conducted for the same high power holding time, and the rod inner pressure change during the tests was measured. The rod inner pressure increase was observed during power change, especially during power reduction. The rod inner pressure increase during a power cycling depended on the length of the high power operation just before the power cycling. The fission gas release during power reduction is estimated to be the release from fission gas bubbles on the grain boundary caused by the thermal stress in the pellet during power reduction. When steady state operation and power cycling were repeated at the power levels of 30, 35 and 40 kW/m, the power cycling accelerated the fission gas release compared with the steady state operation. (author)

  4. Fission Power System Technology for NASA Exploration Missions

    Science.gov (United States)

    Mason, Lee; Houts, Michael

    2011-01-01

    Under the NASA Exploration Technology Development Program, and in partnership with the Department of Energy (DOE), NASA is conducting a project to mature Fission Power System (FPS) technology. A primary project goal is to develop viable system options to support future NASA mission needs for nuclear power. The main FPS project objectives are as follows: 1) Develop FPS concepts that meet expected NASA mission power requirements at reasonable cost with added benefits over other options. 2) Establish a hardware-based technical foundation for FPS design concepts and reduce overall development risk. 3) Reduce the cost uncertainties for FPS and establish greater credibility for flight system cost estimates. 4) Generate the key products to allow NASA decisionmakers to consider FPS as a preferred option for flight development. In order to achieve these goals, the FPS project has two main thrusts: concept definition and risk reduction. Under concept definition, NASA and DOE are performing trade studies, defining requirements, developing analytical tools, and formulating system concepts. A typical FPS consists of the reactor, shield, power conversion, heat rejection, and power management and distribution (PMAD). Studies are performed to identify the desired design parameters for each subsystem that allow the system to meet the requirements with reasonable cost and development risk. Risk reduction provides the means to evaluate technologies in a laboratory test environment. Non-nuclear hardware prototypes are built and tested to verify performance expectations, gain operating experience, and resolve design uncertainties.

  5. Calculation of burnup and power dependence on fission gas released from PWR type reactor fuel element

    International Nuclear Information System (INIS)

    Edy-Sulistyono

    1996-01-01

    Burn up dependence of fission gas released and variation power analysis have been conducted using FEMXI-IV computer code program for Pressure Water Reactor Fuel During steady-state condition. The analysis result shows that the fission gas release is sensitive to the fuel temperature, the increasing of burn up and power in the fuel element under irradiation experiment

  6. A Practical Approach to Starting Fission Surface Power Development

    International Nuclear Information System (INIS)

    Mason, Lee

    2006-01-01

    The Prometheus Power and Propulsion Program has been reformulated to address NASA needs relative to lunar and Mars exploration. Emphasis has switched from the Jupiter Icy Moons Orbiter (JIMO) flight system development to more generalized technology development addressing Fission Surface Power (FSP) and Nuclear Thermal Propulsion (NTP). Current NASA budget priorities and the deferred mission need date for nuclear systems prohibit a fully funded reactor Flight Development Program. However, a modestly funded Advanced Technology Program can and should be conducted to reduce the risk and cost of future flight systems. A potential road-map for FSP technology development leading to possible flight applications could include three elements: 1) Conceptual Design Studies, 2) Advanced Component Technology, and 3) Non-Nuclear System Testing. The Conceptual Design Studies would expand on recent NASA and DOE analyses while increasing the depth of study in areas of greatest uncertainty such as reactor integration and human-rated shielding. The Advanced Component Technology element would address the major technology risks through development and testing of reactor fuels, structural materials, primary loop components, shielding, power conversion, heat rejection, and power management and distribution (PMAD). The Non-Nuclear System Testing would provide a modular, technology test-bed to investigate and resolve system integration issues. (author)

  7. Comparative energetics of three fusion-fission symbiotic nuclear reactor systems

    International Nuclear Information System (INIS)

    Gordon, C.W.; Harms, A.A.

    1975-01-01

    The energetics of three symbiotic fusion-fission nuclear reactor concepts are investigated. The fuel and power balances are considered for various values of systems parameters. The results from this analysis suggest that symbiotic fusion-fission systems are advantageous from the standpoint of economy and resource utilization. (Auth.)

  8. A Two-Phase Cooling Loop for Fission Surface Power Waste Heat Transport, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Current lunar-based Fission Surface Power (FSP) Systems that will support sustained surface outposts consist of a nuclear reactor with power converters, whose waste...

  9. High Efficiency, High Temperature Foam Core Heat Exchanger for Fission Surface Power Systems, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Fission-based power systems with power levels of 30 to ≥100 kWe will be needed for planetary surface bases. Development of high temperature, high efficiency heat...

  10. Power-balance analysis of muon-catalyzed fusion-fission hybrid reactor systems

    International Nuclear Information System (INIS)

    Miller, R.L.; Krakowski, R.A.

    1985-01-01

    A power-balance model of a muon-catalyzed fusion system in the context of a fission-fuel factory is developed and exercised to predict the required physics performance of systems competitive with either pure muon-catalyzed fusion systems or thermonuclear fusion-fission fuel factory hybrid systems

  11. Delayed fission

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukawa, Yuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    Delayed fission is a nuclear decay process that couples {beta} decay and fission. In the delayed fission process, a parent nucleus undergoes {beta} decay and thereby populates excited states in the daughter. If these states are of energies comparable to or greater than the fission barrier of the daughter, then fission may compete with other decay modes of the excited states in the daughter. In this paper, mechanism and some experiments of the delayed fission will be discussed. (author)

  12. Advantages of Production of New Fissionable Nuclides for the Nuclear Power Industry in Hybrid Fusion-Fission Reactors

    Science.gov (United States)

    Tsibulskiy, V. F.; Andrianova, E. A.; Davidenko, V. D.; Rodionova, E. V.; Tsibulskiy, S. V.

    2017-12-01

    A concept of a large-scale nuclear power engineering system equipped with fusion and fission reactors is presented. The reactors have a joint fuel cycle, which imposes the lowest risk of the radiation impact on the environment. The formation of such a system is considered within the framework of the evolution of the current nuclear power industry with the dominance of thermal reactors, gradual transition to the thorium fuel cycle, and integration into the system of the hybrid fusion-fission reactors for breeding nuclear fuel for fission reactors. Such evolution of the nuclear power engineering system will allow preservation of the existing structure with the dominance of thermal reactors, enable the reprocessing of the spent nuclear fuel (SNF) with low burnup, and prevent the dangerous accumulation of minor actinides. The proposed structure of the nuclear power engineering system minimizes the risk of radioactive contamination of the environment and the SNF reprocessing facilities, decreasing it by more than one order of magnitude in comparison with the proposed scheme of closing the uranium-plutonium fuel cycle based on the reprocessing of SNF with high burnup from fast reactors.

  13. Low-Cost Radiator for Fission Power Thermal Control

    Science.gov (United States)

    Maxwell, Taylor; Tarau, Calin; Anderson, William; Hartenstine, John; Stern, Theodore; Walmsley, Nicholas; Briggs, Maxwell

    2014-01-01

    NASA Glenn Research Center (GRC) is developing fission power system technology for future Lunar surface power applications. The systems are envisioned in the 10 to 100kW(sub e) range and have an anticipated design life of 8 to 15 years with no maintenance. NASA GRC is currently setting up a 55 kW(sub e) non-nuclear system ground test in thermal-vacuum to validate technologies required to transfer reactor heat, convert the heat into electricity, reject waste heat, process the electrical output, and demonstrate overall system performance. Reducing the radiator mass, size, and cost is essential to the success of the program. To meet these goals, Advanced Cooling Technologies, Inc. (ACT) and Vanguard Space Technologies, Inc. (VST) are developing a single facesheet radiator with heat pipes directly bonded to the facesheet. The facesheet material is a graphite fiber reinforced composite (GFRC) and the heat pipes are titanium/water. By directly bonding a single facesheet to the heat pipes, several heavy and expensive components can be eliminated from the traditional radiator design such as, POC(TradeMark) foam saddles, aluminum honeycomb, and a second facesheet. A two-heat pipe radiator prototype, based on the single facesheet direct-bond concept, was fabricated and tested to verify the ability of the direct-bond joint to withstand coefficient of thermal expansion (CTE) induced stresses during thermal cycling. The thermal gradients along the bonds were measured before and after thermal cycle tests to determine if the performance degraded. Overall, the results indicated that the initial uniformity of the adhesive was poor along one of the heat pipes. However, both direct bond joints showed no measureable amount of degradation after being thermally cycled at both moderate and aggressive conditions.

  14. Kilowatt-Class Fission Power Systems for Science and Human Precursor Missions

    Science.gov (United States)

    Mason, Lee S.; Gibson, Marc Andrew; Poston, Dave

    2013-01-01

    Nuclear power provides an enabling capability for NASA missions that might otherwise be constrained by power availability, mission duration, or operational robustness. NASA and the Department of Energy (DOE) are developing fission power technology to serve a wide range of future space uses. Advantages include lower mass, longer life, and greater mission flexibility than competing power system options. Kilowatt-class fission systems, designated "Kilopower," were conceived to address the need for systems to fill the gap above the current 100-W-class radioisotope power systems being developed for science missions and below the typical 100-k We-class reactor power systems being developed for human exploration missions. This paper reviews the current fission technology project and examines some Kilopower concepts that could be used to support future science missions or human precursors.

  15. Closed Brayton Cycle Power Conversion Unit for Fission Surface Power Phase I Final Report

    Science.gov (United States)

    Fuller, Robert L.

    2010-01-01

    A Closed Brayton cycle power conversion system has been developed to support the NASA fission surface power program. The goal is to provide electricity from a small nuclear reactor heat source for surface power production for lunar and Mars environments. The selected media for a heat source is NaK 78 with water as a cooling source. The closed Brayton cycle power was selected to be 12 kWe output from the generator terminals. A heat source NaK temperature of 850 K plus or minus 25 K was selected. The cold source water was selected at 375 K plus or minus 25 K. A vacuum radiation environment of 200 K is specified for environmental operation. The major components of the system are the power converter, the power controller, and the top level data acquisition and control unit. The power converter with associated sensors resides in the vacuum radiation environment. The power controller and data acquisition system reside in an ambient laboratory environment. Signals and power are supplied across the pressure boundary electrically with hermetic connectors installed on the vacuum vessel. System level analyses were performed on working fluids, cycle design parameters, heater and cooling temperatures, and heat exchanger options that best meet the needs of the power converter specification. The goal is to provide a cost effective system that has high thermal-to-electric efficiency in a compact, lightweight package.

  16. Reference reactor module for NASA's lunar surface fission power system

    Energy Technology Data Exchange (ETDEWEB)

    Poston, David I [Los Alamos National Laboratory; Kapernick, Richard J [Los Alamos National Laboratory; Dixon, David D [Los Alamos National Laboratory; Werner, James [INL; Qualls, Louis [ORNL; Radel, Ross [SNL

    2009-01-01

    Surface fission power systems on the Moon and Mars may provide the first US application of fission reactor technology in space since 1965. The Affordable Fission Surface Power System (AFSPS) study was completed by NASA/DOE to determine the cost of a modest performance, low-technical risk surface power system. The AFSPS concept is now being further developed within the Fission Surface Power (FSP) Project, which is a near-term technology program to demonstrate system-level TRL-6 by 2013. This paper describes the reference FSP reactor module concept, which is designed to provide a net power of 40 kWe for 8 years on the lunar surface; note, the system has been designed with technologies that are fully compatible with a Martian surface application. The reactor concept uses stainless-steel based. UO{sub 2}-fueled, pumped-NaK fission reactor coupled to free-piston Stirling converters. The reactor shielding approach utilizes both in-situ and launched shielding to keep the dose to astronauts much lower than the natural background radiation on the lunar surface. The ultimate goal of this work is to provide a 'workhorse' power system that NASA can utilize in near-term and future Lunar and Martian mission architectures, with the eventual capability to evolve to very high power, low mass systems, for either surface, deep space, and/or orbital missions.

  17. Tokamak hybrid thermonuclear reactor for the production of fissionable fuel and electric power

    International Nuclear Information System (INIS)

    Velikhov, E.P.; Glukhikh, V.A.; Gur'ev, V.V.

    1978-01-01

    The results of feasibility studies of a tokamak- based hybrid reactor concept are presented. The system selected has a D-T plasma volume of 575 m 3 with additional plasma heating by injection of fast neutral particles. The method of heating makes it possible to achieve an economical two-component tokamak regime at ntau=(4-6)x10 13 sxcm -3 , i e. far below the Lawson criterion. Plasma and vacuum chamber are surrounded by a blanket where fissionable plutonium is produced and heat transformed into electric power is generated. Major plasma-neutron-physical characteristics of the 6905 MWth (2500 MWe) reactor and its electromagnetic system are presented. Evaluations show that the hybrid reactor can produce about 800 kg of Pu per 1GWth/yr as compared to 70-150 kg of Pu for fast breeder reactors. The increased Pu production rate is the major merit of the concept promising for both power generation and fuelling thermal fission reactions

  18. Fission power: a search for a ''second-generation'' reactor

    International Nuclear Information System (INIS)

    Hovingh, J.

    1985-01-01

    This report touches on the history of US fission reactors and explores the current technical status of such reactors around the world, including experimental reactors. Its purpose is to identify, evaluate, and rank the most promising concepts among existing reactors, proposed but unadopted designs, and what can be described as ''new'' concepts. Also discussed are such related concerns as utility requirements and design considerations. The report concludes with some recommendations for possible future LLNL involvement

  19. Improving the safety of future nuclear fission power plants

    International Nuclear Information System (INIS)

    Frisch, W.; Gros, G.

    2001-01-01

    The main objectives and principles in nuclear fission reactor safety are presented, e.g. the defence in depth strategy and technical principles such as redundancy, diversity and physical separation. After a brief historical review of the continuous development of safety improvement, the most recent international discussion is presented. This includes mainly the international activities within IAEA and its International Nuclear Safety Advisory Group (INSAG). The safety improvement, presented in recommendations of IAEA and INSAG is expressed as an improvement of all elements and all levels of the defence in depth concept. Special emphasis is put on improvement of the highest level, which requires the implementation of means to mitigate consequences of accidents with severe core damage. The different future concepts are briefly characterised. Some examples from the French-German safety approach are taken to demonstrate how requirements for safety improvement by means of an enhancement of the defence in depth principle are developed

  20. Study of advanced fission power reactor development for the United States. Volume I

    International Nuclear Information System (INIS)

    1976-01-01

    This volume summarizes the results and conclusions of an assessment of five advanced fission power reactor concepts in the context of potential nuclear power economies developed over the time period 1975 to 2020. The study was based on the premise that the LMFBR program has been determined to be the highest priority fission reactor program and it will proceed essentially as planned. Accepting this fact, the overall objective of the study was to provide evaluations of advanced fission reactor systems for input to evaluating the levels of research and development funding for fission power. Evaluation of the reactor systems included the following categories: (1) power plant performance, (2) fuel resource utilization; (3) fuel-cycle requirements; (4) economics; (5) environmental impact; (6) risk to the public; and (7) R and D requirements to achieve commercial status. The specific major objectives of the study were twofold: (1) to parametrically assess the impact of various reactor types for various levels of power demand through the year 2020 on fissile fuel utilization, economics, and the environment, based on varying but reasonable assumptions on the rates of installation; and (2) to qualitatively assess the practicality of the advanced reactor concepts, and their research and development. The reactor concepts examined were limited to the following: advanced high-temperature, gas-cooled reactor (HTGR) systems including the thorium/U-233 fuel cycle, gas turbine, and binary cycle (BIHTGR); gas-cooled fast breeder reactor (GCFR); molten salt breeder reactor (MSBR); light water breeder reactor (LWBR); and CANDU heavy water reactor

  1. Fission nuclear power prospects and its role in meeting global energy needs

    International Nuclear Information System (INIS)

    Golan, S.

    1992-01-01

    Nuclear power currently makes an important contribution to world's energy requirements providing 17% of its electricity. But as global warming becomes of greater concern, many ask whether nuclear power can and should contribute more. The author, who is involved in the nuclear power enterprise for 35 years, tries to answer this question affirmative. He holds the view that: a) nuclear fission power is essential to meeting world's energy needs without unduly impairing the global environment; b) by possessing the required attributes discussed in this paper, nuclear fission power can be made societally acceptable; c) the industrialized world should accelerate LMFR deployment while fostering more convenient energy alternatives for the developing world; and d) the HTGR is unique in its ability to augment non-electricity energy needs and could become the technology choice of developing countries for nuclear electricity production. (author). 5 refs., 5 figs., 4 tabs

  2. A method for measuring power signal background and source strength in a fission reactor

    International Nuclear Information System (INIS)

    Baers, B.; Kall, L.; Visuri, P.

    1977-01-01

    Theory and experimental verification of a novel method for measuring power signal bias and source strength in a fission reactor are reported. A minicomputer was applied in the measurements. The method is an extension of the inverse kinetics method presented by Mogilner et al. (Auth.)

  3. Transfer parameters of fission and activation products present in effluents of nuclear power reactors

    International Nuclear Information System (INIS)

    Cancio, D.; Menossi, C.A.; Ciallella, N.R.

    1978-01-01

    The paper presents results of research carried out in Argentina on transfer parameters of fission and activation products which may be present in the effluents of nuclear power reactors. For some nuclides, as Sr-90, Co-137 and I-131, the parameters were obtained by studies of the fallout, from measurements of integrated levels in the environment and in the food chains. Other values are concentration factors derived from laboratory and field experiments. They refer to fish, molluscs, crustaces and fresh water plants, for several fission and activation nuclides. Transfer parameters obtained have been of significant importance for environmental assessments, relating to nuclear installations in Argentina. (author)

  4. Heat Pipe Powered Stirling Conversion for the Demonstration Using Flattop Fission (DUFF) Test

    Science.gov (United States)

    Gibson, Marc A.; Briggs, Maxwell H.; Sanzi, James L.; Brace, Michael H.

    2013-01-01

    Design concepts for small Fission Power Systems (FPS) have shown that heat pipe cooled reactors provide a passive, redundant, and lower mass option to transfer heat from the fuel to the power conversion system, as opposed to pumped loop designs typically associated with larger FPS. Although many systems have been conceptually designed and a few making it to electrically heated testing, none have been coupled to a real nuclear reactor. A demonstration test named DUFF Demonstration Using Flattop Fission, was planned by the Los Alamos National Lab (LANL) to use an existing criticality experiment named Flattop to provide the nuclear heat source. A team from the NASA Glenn Research Center designed, built, and tested a heat pipe and power conversion system to couple to Flattop with the end goal of making electrical power. This paper will focus on the design and testing performed in preparation for the DUFF test.

  5. Control of a laser inertial confinement fusion-fission power plant

    Science.gov (United States)

    Moses, Edward I.; Latkowski, Jeffery F.; Kramer, Kevin J.

    2015-10-27

    A laser inertial-confinement fusion-fission energy power plant is described. The fusion-fission hybrid system uses inertial confinement fusion to produce neutrons from a fusion reaction of deuterium and tritium. The fusion neutrons drive a sub-critical blanket of fissile or fertile fuel. A coolant circulated through the fuel extracts heat from the fuel that is used to generate electricity. The inertial confinement fusion reaction can be implemented using central hot spot or fast ignition fusion, and direct or indirect drive. The fusion neutrons result in ultra-deep burn-up of the fuel in the fission blanket, thus enabling the burning of nuclear waste. Fuels include depleted uranium, natural uranium, enriched uranium, spent nuclear fuel, thorium, and weapons grade plutonium. LIFE engines can meet worldwide electricity needs in a safe and sustainable manner, while drastically shrinking the highly undesirable stockpiles of depleted uranium, spent nuclear fuel and excess weapons materials.

  6. Nuclear power ecology: comparative analysis

    International Nuclear Information System (INIS)

    Trofimenko, A.P.; Lips'ka, A.Yi.; Pisanko, Zh.Yi.

    2005-01-01

    Ecological effects of different energy sources are compared. Main actions for further nuclear power development - safety increase and waste management, are noted. Reasons of restrained public position to nuclear power and role of social and political factors in it are analyzed. An attempt is undertaken to separate real difficulties of nuclear power from imaginary ones that appear in some mass media. International actions of environment protection are noted. Risk factors at different energy source using are compared. The results of analysis indicate that ecological influence and risk for nuclear power are of minimum

  7. Fission-powered in-core thermoacoustic sensor

    Energy Technology Data Exchange (ETDEWEB)

    Garrett, Steven L. [Graduate Program in Acoustics, Penn State University, University Park, Pennsylvania 16802 (United States); Smith, James A. [Fundamental Fuel Properties, Idaho National Laboratory, Idaho Falls, Idaho 83415 (United States); Smith, Robert W. M. [Applied Research Laboratory, Penn State University, State College, Pennsylvania 16804 (United States); Heidrich, Brenden J. [Nuclear Science User Facilities, Idaho National Laboratory, Idaho Falls, Idaho 83415 (United States); Heibel, Michael D. [Global Technology Development, Westinghouse Electric Company, Cranberry Township, Pennsylvania 16066 (United States)

    2016-04-04

    A thermoacoustic engine is operated within the core of a nuclear reactor to acoustically telemeter coolant temperature (frequency-encoded) and reactor power level (amplitude-encoded) outside the reactor, thus providing the values of these important parameters without external electrical power or wiring. We present data from two hydrophones in the coolant (far from the core) and an accelerometer attached to a structure outside the reactor. These signals have been detected even in the presence of substantial background noise generated by the reactor's fluid pumps.

  8. Comparison of Thermal Neutron Flux Measured by Uranium 235 Fission Chamber and Rhodium Self-Powered Neutron Detector in MTR

    International Nuclear Information System (INIS)

    Fourmentel, D.; Filliatre, P.; Barbot, L.; Villard, J.-F.; Lyoussi, A.; Geslot, B.; Malo, J.-Y.; Carcreff, H.; Reynard-Carette, C.

    2013-06-01

    Thermal neutron flux is one of the most important nuclear parameter to be measured on-line in Material Testing Reactors (MTRs). In particular two types of sensors with different physical operating principles are commonly used: self-powered neutron detectors (SPND) and fission chambers with uranium 235 coating. This work aims to compare on one hand the thermal neutron flux evaluation given by these two types of sensors and on the other hand to compare these evaluations with activation dosimeter measurements, which are considered as the reference for absolute neutron flux assessment. This study was conducted in an irradiation experiment, called CARMEN-1, performed during 2012 in OSIRIS reactor (CEA Saclay - France). The CARMEN-1 experiment aims to improve the neutron and photon flux and nuclear heating measurements in MTRs. In this paper we focus on the thermal neutron flux measurements performed in CARMEN-1 experiment. The use of fission chambers to measure the absolute thermal neutron flux in MTRs is not very usual. An innovative calibration method for fission chambers operated in Campbell mode has been developed at the CEA Cadarache (France) and tested for the first time in the CARMEN-1 experiment. The results of these measurements are discussed, with the objective to measure with the best accuracy the thermal neutron flux in the future Jules Horowitz Reactor. (authors)

  9. Planetary Surface Power and Interstellar Propulsion Using Fission Fragment Magnetic Collimator Reactor

    International Nuclear Information System (INIS)

    Tsvetkov, Pavel V.; Hart, Ron R.; King, Don B.; Rochau, Gary E.

    2006-01-01

    Fission energy can be used directly if the kinetic energy of fission fragments is converted to electricity and/or thrust before turning into heat. The completed US DOE NERI Direct Energy Conversion (DEC) Power Production project indicates that viable DEC systems are possible. The US DOE NERI DEC Proof of Principle project began in October of 2002 with the goal to demonstrate performance principles of DEC systems. One of the emerging DEC concepts is represented by fission fragment magnetic collimator reactors (FFMCR). Safety, simplicity, and high conversion efficiency are the unique advantages offered by these systems. In the FFMCR, the basic energy source is the kinetic energy of fission fragments. Following escape from thin fuel layers, they are captured on magnetic field lines and are directed out of the core and through magnetic collimators to produce electricity and thrust. The exiting flow of energetic fission fragments has a very high specific impulse that allows efficient planetary surface power and interstellar propulsion without carrying any conventional propellant onboard. The objective of this work was to determine technological feasibility of the concept. This objective was accomplished by producing the FFMCR design and by analysis of its performance characteristics. The paper presents the FFMCR concept, describes its development to a technologically feasible level and discusses obtained results. Performed studies offer efficiencies up to 90% and velocities approaching speed of light as potentially achievable. The unmanned 10-tons probe with 1000 MW FFMCR propulsion unit would attain mission velocity of about 2% of the speed of light. If the unit is designed for 4000 MW, then in 10 years the unmanned 10-tons probe would attain mission velocity of about 10% of the speed of light

  10. High-power proton linac for transmuting the long-lived fission products in nuclear waste

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, G.P.

    1991-01-01

    High power proton linacs are being considered at Los Alamos as drivers for high-flux spallation neutron sources that can be used to transmute the troublesome long-lived fission products in defense nuclear waste. The transmutation scheme being studied provides a high flux (> 10{sup 16}/cm{sup 2}{minus}s) of thermal neutrons, which efficiently converts fission products to stable or short-lived isotopes. A medium-energy proton linac with an average beam power of about 110 MW can burn the accumulated Tc99 and I129 inventory at the DOE's Hanford Site within 30 years. Preliminary concepts for this machine are described. 3 refs., 5 figs., 2 tabs.

  11. Burnout and gate rupture of power MOS transistors with fission fragments of 252Cf

    International Nuclear Information System (INIS)

    Tang Benqi; Wang Yanping; Geng Bin; Chen Xiaohua; He Chaohui; Yang Hailiang

    2000-01-01

    A study to determine the single event burnout (SEB) and single event gate rupture (SEGR) sensitivities of power MOSFET devices is carried out by exposure to fission fragments from 252 Cf source. The test method, test results, a description of observed burnout current waveforms and a discussion of a possible failure mechanism are presented. The test results include the observed dependence upon applied drain or gate to source bias and effect of external capacitors and limited resistors

  12. Industrial development of neutron detectors, fission chambers, self powered detectors, ionization chambers

    International Nuclear Information System (INIS)

    Constans, H.; Coville, P.; Guerre, J.

    1975-01-01

    Reactor control requires the determination of neutron flux at all times. The needed characteristics lead to use of several types of detectors: boron lined counters, boron lined ionization chambers, fission ionization chambers and self powered detectors. The principle of the reaction involved the fabrication requirements, the different modes of utilization and the characteristics obtained are examined for each detector. The problem of electric connections in the active area has been solved by developing ''integrated cables'' [fr

  13. Physics and potentials of fissioning plasmas for space power and propulsion

    Science.gov (United States)

    Thom, K.; Schwenk, F. C.; Schneider, R. T.

    1976-01-01

    Fissioning uranium plasmas are the nuclear fuel in conceptual high-temperature gaseous-core reactors for advanced rocket propulsion in space. A gaseous-core nuclear rocket would be a thermal reactor in which an enriched uranium plasma at about 10,000 K is confined in a reflector-moderator cavity where it is nuclear critical and transfers its fission power to a confining propellant flow for the production of thrust at a specific impulse up to 5000 sec. With a thrust-to-engine weight ratio approaching unity, the gaseous-core nuclear rocket could provide for propulsion capabilities needed for manned missions to the nearby planets and for economical cislunar ferry services. Fueled with enriched uranium hexafluoride and operated at temperatures lower than needed for propulsion, the gaseous-core reactor scheme also offers significant benefits in applications for space and terrestrial power. They include high-efficiency power generation at low specific mass, the burnup of certain fission products and actinides, the breeding of U-233 from thorium with short doubling times, and improved convenience of fuel handling and processing in the gaseous phase.

  14. Comparative measurements of independent yields of 239Pu fission fragments induced by thermal and resonance neutrons

    International Nuclear Information System (INIS)

    Gundorin, N.A.; Kopach, Y.N.; Telezhnikov, S.A.

    1994-01-01

    The independent yields of 239 Pu fission fragments by means of gamma-spectroscopy method were measured for light and heavy groups on the IBR-30 reactor in Dubna. Comparative analysis of experimental data for fission induced by thermal and resonance neutrons was performed. The possibilities to increase the measurement's precision consist of the employment of a HPGe detector with high efficiency and its open-quotes activeclose quotes shielding in the gamma spectrometer, as well as a high speed electronics system. In this way the number of identified fragments will be increased and independent yields will be measured to a precision of 1-3%. Measurements at the source with shorter neutron pulse duration to increase neutron energy resolution will be possible after the reconstruction of a modern neutron source in Dubna in accordance with the IREN project

  15. Radar Men on the Moon: A Brief Survey of Fission Surface Power Studies

    International Nuclear Information System (INIS)

    Bennett, Gary L.

    2008-01-01

    This paper reviews some of the salient fission surface power studies, including those dating back to the early SNAP (Systems for Nuclear Auxiliary Power) program. Particular attention will be focused on the more recent Space Exploration Initiative (including the related Synthesis Group report) and Vision for Space Exploration. Commonalties in these studies will be noted; for example, many studies have shown that powers in the range of 100 kWe are required for human-tended bases on the Moon and Mars. Just as advanced human civilizations depend upon electrical power so will advanced, human-occupied lunar and Mars bases with powers rising into the megawatt level for bases with manufacturing and resource utilization capabilities. The role of radioisotope power sources will also be noted

  16. Radar Men on the Moon: A Brief Survey of Fission Surface Power Studies

    Science.gov (United States)

    Bennett, Gary L.

    2008-01-01

    This paper reviews some of the salient fission surface power studies, including those dating back to the early SNAP (Systems for Nuclear Auxiliary Power) program. Particular attention will be focused on the more recent Space Exploration Initiative (including the related Synthesis Group report) and Vision for Space Exploration. Commonalties in these studies will be noted; for example, many studies have shown that powers in the range of 100 kWe are required for human-tended bases on the Moon and Mars. Just as advanced human civilizations depend upon electrical power so will advanced, human-occupied lunar and Mars bases with powers rising into the megawatt level for bases with manufacturing and resource utilization capabilities. The role of radioisotope power sources will also be noted.

  17. Gamma-ray spectrometric measurements of fission rate ratios between fresh and burnt fuel following irradiation in a zero-power reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kröhnert, H., E-mail: hanna.kroehnert@ensi.ch [Paul Scherrer Institut (PSI), CH-5232 Villigen (Switzerland); École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Perret, G.; Murphy, M.F. [Paul Scherrer Institut (PSI), CH-5232 Villigen (Switzerland); Chawla, R. [Paul Scherrer Institut (PSI), CH-5232 Villigen (Switzerland); École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

    2013-01-11

    The gamma-ray activity from short-lived fission products has been measured in fresh and burnt UO{sub 2} fuel samples after irradiation in a zero-power reactor. For the first time, short-lived gamma-ray activity from fresh and burnt fuel has been compared and fresh-to-burnt fuel fission rate ratios have been derived. For the measurements, well characterized fresh and burnt fuel samples, with burn-ups up to 46 GWd/t, were irradiated in the zero-power research reactor PROTEUS. Fission rate ratios were derived based on the counting of high-energy gamma-rays above 2200 keV, in order to discriminate against the high intrinsic activity of the burnt fuel. This paper presents the measured fresh-to-burnt fuel fission rate ratios based on the {sup 142}La (2542 keV), {sup 89}Rb (2570 keV), {sup 138}Cs (2640 keV) and {sup 95}Y (3576 keV) high-energy gamma-ray lines. Comparisons are made with the results of Monte Carlo modeling of the experimental configuration, carried out using the MCNPX code. The measured fission rate ratios have 1σ uncertainties of 1.7–3.4%. The comparisons with calculated predictions show an agreement within 1–3σ, although there appears to be a slight bias (∼3%).

  18. Systems Modeling For The Laser Fusion-Fission Energy (LIFE) Power Plant

    International Nuclear Information System (INIS)

    Meier, W.R.; Abbott, R.; Beach, R.; Blink, J.; Caird, J.; Erlandson, A.; Farmer, J.; Halsey, W.; Ladran, T.; Latkowski, J.; MacIntyre, A.; Miles, R.; Storm, E.

    2008-01-01

    A systems model has been developed for the Laser Inertial Fusion-Fission Energy (LIFE) power plant. It combines cost-performance scaling models for the major subsystems of the plant including the laser, inertial fusion target factory, engine (i.e., the chamber including the fission and tritium breeding blankets), energy conversion systems and balance of plant. The LIFE plant model is being used to evaluate design trade-offs and to identify high-leverage R and D. At this point, we are focused more on doing self consistent design trades and optimization as opposed to trying to predict a cost of electricity with a high degree of certainty. Key results show the advantage of large scale (>1000 MWe) plants and the importance of minimizing the cost of diodes and balance of plant cost

  19. Comparative studies of actinide and sub-actinide fission cross section calculation from MCNP6 and TALYS

    International Nuclear Information System (INIS)

    Perkasa, Y. S.; Waris, A.; Kurniadi, R.; Su'ud, Z.

    2014-01-01

    Comparative studies of actinide and sub-actinide fission cross section calculation from MCNP6 and TALYS have been conducted. In this work, fission cross section resulted from MCNP6 prediction will be compared with result from TALYS calculation. MCNP6 with its event generator CEM03.03 and LAQGSM03.03 have been validated and verified for several intermediate and heavy nuclides fission reaction data and also has a good agreement with experimental data for fission reaction that induced by photons, pions, and nucleons at energy from several ten of MeV to about 1 TeV. The calculation that induced within TALYS will be focused mainly to several hundred MeV for actinide and sub-actinide nuclides and will be compared with MCNP6 code and several experimental data from other evaluator

  20. Highly efficient power system based on direct fission fragment energy conversion utilizing magnetic collimation

    International Nuclear Information System (INIS)

    Tsvetkov, Pavel V.; Hart, Ron R.; Parish, Theodore A.

    2003-01-01

    The present study was focused on developing a technologically feasible power system that is based on direct fission fragment energy conversion utilizing magnetic collimation. The new concept is an attempt to combine several advantageous design solutions, which have been proposed for application in both fission and fusion reactors, into one innovative system that can offer exceptional energy conversion efficiency. The analysis takes into consideration a wide range of operational aspects including fission fragment escape from the fuel, collimation, collection, criticality, long-term performance, energy conversion efficiency, heat removal, and safety characteristics. Specific characteristics of the individual system components and the entire system are evaluated. Consistent analysis and evaluation of the technological feasibility of the concept were achieved using state-of-the-art computer codes that allowed realistic and consistent modeling. The calculated energy conversion efficiencies for the presented designs without a thermodynamic cycle and with the heavy water cycle are 52% and 62%, respectively. The analysis indicates that efficiencies up to 90% are potentially achievable. (author)

  1. Development of a fission product transport module predicting the behavior of radiological materials during sever accidents in a nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hyung Seok; Rhee, Bo Wook; Kim, Dong Ha [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-09-15

    Korea Atomic Energy Research Institute is developing a fission product transport module for predicting the behavior of radioactive materials in the primary cooling system of a nuclear power plant as a separate module, which will be connected to a severe accident analysis code, Core Meltdown Progression Accident Simulation Software (COMPASS). This fission product transport (COMPASS-FP) module consists of a fission product release model, an aerosol generation model, and an aerosol transport model. In the fission product release model there are three submodels based on empirical correlations, and they are used to simulate the fission product gases release from the reactor core. In the aerosol generation model, the mass conservation law and Raoult's law are applied to the mixture of vapors and droplets of the fission products in a specified control volume to find the generation of the aerosol droplet. In the aerosol transport model, empirical correlations available from the open literature are used to simulate the aerosol removal processes owing to the gravitational settling, inertia impaction, diffusiophoresis, and thermophoresis. The COMPASS-FP module was validated against Aerosol Behavior Code Validation and Evaluation (ABCOVE-5) test performed by Hanford Engineering Development Laboratory for comparing the prediction and test data. The comparison results assuming a non-spherical aerosol shape for the suspended aerosol mass concentration showed a good agreement with an error range of about ±6%. It was found that the COMPASS-FP module produced the reasonable results of the fission product gases release, the aerosol generation, and the gravitational settling in the aerosol removal processes for ABCOVE-5. However, more validation for other aerosol removal models needs to be performed.

  2. Summary of the Manufacture, Testing and Model Validation of a Full-Scale Radiator for Fission Surface Power Applications

    Science.gov (United States)

    Ellis, David L.; Calder, James; Siamidis, John

    2011-01-01

    A full-scale radiator for a lunar fission surface power application was manufactured by Material innovations, Inc., for the NASA Glenn Research Center. The radiator was designed to reject 6 kWt with an inlet water temperature of 400 K and a water mass flow rate of 0.5 kg/s. While not flight hardware, the radiator incorporated many potential design features and manufacturing techniques for future flight hardware. The radiator was tested at NASA Glenn Research Center for heat rejection performance. The results showed that the radiator design was capable of rejecting over 6 kWt when operating at the design conditions. The actual performance of the radiator as a function of operational manifolds, inlet water temperature and facility sink temperature was compared to the predictive model developed by NASA Glenn Research Center. The results showed excellent agreement with the model with the actual average face sheet temperature being within 1% of the predicted value. The results will be used in the design and production of NASA s next generation fission power heat rejection systems. The NASA Glenn Research Center s Technology Demonstration Unit will be the first project to take advantage of the newly developed manufacturing techniques and analytical models.

  3. Design of a Mechanical NaK Pump for Fission Space Power Systems

    Science.gov (United States)

    Mireles, Omar R.; Bradley, David; Godfroy, Thomas

    2010-01-01

    Alkali liquid metal cooled fission reactor concepts are under development for mid-range spaceflight power requirements. One such concept utilizes a sodium-potassium eutectic (NaK) as the primary loop working fluid. Traditionally, linear induction pumps have been used to provide the required flow and head conditions for liquid metal systems but can be limited in performance. This paper details the design, build, and check-out test of a mechanical NaK pump. The pump was designed to meet reactor cooling requirements using commercially available components modified for high temperature NaK service.

  4. In-reactor testing of self-powered neutron detectors and miniature fission chambers

    International Nuclear Information System (INIS)

    Duchene, J.; LeMeur, R.; Verdant, R.

    1975-01-01

    The CEA has tested a variety of ''slow'' self-powered neutron detectors with rhodium, silver and vanadium emitters. Currently there are 120 vanadium detectors in the EL4 heavy water reactor. In addition, ''fast'' detectors with cobalt emitters have been tested at Saclay and 50 of these are in reactor. Other studies are concerned with 6 mm diameter miniature fission chambers. Two fast response chambers with argon-nitrogen filling gas became slow during irradiation, but operated to 600 deg C. An argon filled chamber of 4.7 mm diameter, for traversing in core system in pressurized water reactor, has shown satisfactory test results. (author)

  5. Nuclear power plant with improved arrangements for the removal of post fission and emergency heating

    International Nuclear Information System (INIS)

    Buescher, E.; Vinzens, K.

    1977-01-01

    This is concerned with additional equipment for emergency heat removal in a sodium cooled reactor, which operates on failure of the post fission heat removal system. The space for pressure relieving spaces and concrete masses as heat sinks within the reactor cell is no longer required. In this nuclear power plant, a heat exchanger chain transmits heat and power: There is a first sodium circuit between pressure vessel and the first heat exchanger, a second one between the first and second heat excahngers, and a third (Steam) circuit with turbine, condenser and return pump. A fourth circuit connects the secondary side of the condenser with a cooling tower. There is a threee component heat excahgner in the primary circuit after the first heat exchanger, which is built around the first heat exchanger, and is sealed into an unloading space. This space is situated next to the reactor cell and is above the operating level of the sodium in the pressure vessel. It is connected to the cell by an upper duct, normally closed by a bursting disc, and by a lower duct. In the three comopnent heat exchanger, a liquid lead-bismuth eutectic mixture transmits the heat from sodium pipes to water pipes. In normal operation it is used for steam superheating or feedwater preheating. The three component heat exchanger bridges the first and second heat exchangers as an emergency heat exchanger. If in such a case the post fission heat removal has failed, the sodium evaporating in the pressure vessel flows into the unloading space and condenses on the ribs of the emergency heat exchanger. The post fission heat is fed by the water secondary medium directly into the tertiary circuit. The sodium condensate flows back from the unloading space via the lower duct into the reactor cell and maintains the emergency level there. (RW) 891 RW [de

  6. Uncertainties on decay heat power due to fission product data uncertainties; Incertitudes sur la puissance residuelle dues aux incertitudes sur les donnees de produits de fission

    Energy Technology Data Exchange (ETDEWEB)

    Rebah, J

    1998-08-01

    Following a reactor shutdown, after the fission process has completely faded out, a significant quantity of energy known as 'decay heat' continues to be generated in the core. The knowledge with a good precision of the decay heat released in a fuel after reactor shutdown is necessary for: residual heat removal for normal operation or emergency shutdown condition, the design of cooling systems and spent fuel handling. By the summation calculations method, the decay heat is equal to the sum of the energies released by individual fission products. Under taking into account all nuclides that contribute significantly to the total decay heat, the results from summation method are comparable with the measured ones. Without the complete covariance information of nuclear data, the published uncertainty analyses of fission products decay heat summation calculation give underestimated errors through the variance/covariance analysis in consideration of correlation between the basic nuclear data, we calculate in this work the uncertainties on the decay heat associated with the summation calculations. Contribution to the total error of decay heat comes from uncertainties in three terms: fission yields, half-lives and average beta and gamma decay energy. (author)

  7. Source driven breeding fission power reactors and the nuclear energy strategy

    International Nuclear Information System (INIS)

    Greenspan, E.

    The nuclear energy economy is facing severe difficulties associated with low utilization of uranium resources, safety, non-proliferation and environmental issues. Energy policy makers face the dilemma: commercialize LMFBRs immediately with the risk of negative economical, proliferation or other consequences, or continue with R and D programs that will provide the information needed for sounder decisions, but now taking the risk of running out of economically exploitable uranium ore resources. The development of hybrid reactors can provide an assurance against the latter risk and offers many interesting new options for the nuclear energy strategy. Being based on the technology of LWRs and HWRs, Light Water Hybrid Reactors (LWHR) provide a most natural link between the fission reactor technology of the present and the fusion power technology of the future. The investment in their development in excess of that required for the development of fusion power reactors is expected to be relatively small, thus making the development of LWHRs potentially a high benefit-to-cost ratio program. It is recommended that the fission and fusion communities will cooperate in hybrids R and D programs aimed at assessing the technological and economical viability of hybrid reactors as reliably and soon as possible. (author)

  8. Local Fission Gas Release and Swelling in Water Reactor Fuel during Slow Power Transients

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Walker, C.T.; Ray, I.L.F.

    1985-01-01

    Gas release and fuel swelling caused by a power increase in a water reactor fuel (burn-up 2.7–4.5% FIMA) is described. At a bump terminal level of about 400 W/cm (local value) gas release was 25–40%. The formation of gas bubbles on grain boundaries and their degree of interlinkage are the two...... factors that determine the level of fission gas release during a power bump. Release begins when gas bubbles on grain boundaries start o interlink. This occurred at r/r0 ~ 0.75. Release tunnels were fully developed at r/r0 ~ 0.55 with the result that gas release was 60–70% at this position....

  9. Ternary fission

    International Nuclear Information System (INIS)

    Wagemans, C.

    1991-01-01

    Since its discovery in 1946, light (charged) particle accompanied fission (ternary fission) has been extensively studied, for spontaneous as well as for induced fission reactions. The reason for this interest was twofold: the ternary particles being emitted in space and time close to the scission point were expected to supply information on the scission point configuration and the ternary fission process was an important source of helium, tritium, and hydrogen production in nuclear reactors, for which data were requested by the nuclear industry. Significant experimental progress has been realized with the advent of high-resolution detectors, powerful multiparameter data acquisition systems, and intense neutron and photon beams. As far as theory is concerned, the trajectory calculations (in which scission point parameters are deduced from the experimental observations) have been very much improved. An attempt was made to explain ternary particle emission in terms of a Plateau-Rayleigh hydrodynamical instability of a relatively long cylindrical neck or cylindrical nucleus. New results have also been obtained on the so-called open-quotes trueclose quotes ternary fission (fission in three about-equal fragments). The spontaneous emission of charged particles has also clearly been demonstrated in recent years. This chapter discusses the main characteristics of ternary fission, theoretical models, light particle emission probabilities, the dependence of the emission probabilities on experimental variables, light particle energy distributions, light particle angular distributions, correlations between light particle accompanied fission observables, open-quotes trueclose quotes ternary fission, and spontaneous emission of heavy ions. 143 refs., 18 figs., 8 tabs

  10. Review of the safety concept for fusion reactor concepts and transferability of the nuclear fission regulation to potential fusion power plants

    Energy Technology Data Exchange (ETDEWEB)

    Raeder, Juergen; Weller, Arthur; Wolf, Robert [Max-Planck-Institut fuer Plasmaphysik (IPP), Garching (Germany); Jin, Xue Zhou; Boccaccini, Lorenzo V.; Stieglitz, Robert; Carloni, Dario [Karlsruher Institute fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany); Pistner, Christoph [Oeko-Institut e.V., Darmstadt (Germany); Herb, Joachim [Gesellschaft fuer Anlagen- und Reaktorsicherheit, Koeln (Germany)

    2016-01-15

    This paper summarizes the current state of the art in science and technology of the safety concept for future fusion power plants (FPPs) and examines the transferability of the current nuclear fission regulation to the concepts of future fusion power plants. At the moment there exist only conceptual designs of future fusion power plants. The most detailed concepts with regards to safety aspects were found in the European Power Plant Conceptual Study (PPCS). The plant concepts discussed in the PPCS are based on magnetic confinement of the plasma. The safety concept of fusion power plants, which has been developed during the last decades, is based on the safety concepts of installations with radioactive inventories, especially nuclear fission power plants. It applies the concept of defence in depth. However, there are specific differences between the implementations of the safety concepts due to the physical and technological characteristics of fusion and fission. It is analysed whether for fusion a safety concept is required comparable to the one of fission. For this the consequences of a purely hypothetical release of large amounts of the radioactive inventory of a fusion power plant and a fission power plant are compared. In such an event the evacuation criterion outside the plant is exceeded by several orders of magnitude for a fission power plant. For a fusion power plant the expected radiological consequences are of the order of the evacuation criterion. Therefore, a safety concept is also necessary for fusion to guarantee the confinement of the radioactive inventory. The comparison between the safety concepts for fusion and fission shows that the fundamental safety function ''confinement of the radioactive materials'' can be transferred directly in a methodical way. For a fusion power plant this fundamental safety function is based on both, physical barriers as well as on active retention functions. After the termination of the fusion

  11. Development of NASA's Small Fission Power System for Science and Human Exploration

    Science.gov (United States)

    Gibson, Marc A.; Mason, Lee S.; Bowman, Cheryl L.; Poston, David I.; McClure, Patrick R.; Creasy, John; Robinson, Chris

    2015-01-01

    Exploration of our solar system has brought many exciting challenges to our nations scientific and engineering community over the past several decades. As we expand our visions to explore new, more challenging destinations, we must also expand our technology base to support these new missions. NASAs Space Technology Mission Directorate is tasked with developing these technologies for future mission infusion and continues to seek answers to many existing technology gaps. One such technology gap is related to compact power systems (1 kWe) that provide abundant power for several years where solar energy is unavailable or inadequate. Below 1 kWe, Radioisotope Power Systems have been the workhorse for NASA and will continue to be used for lower power applications similar to the successful missions of Voyager, Ulysses, New Horizons, Cassini, and Curiosity. Above 1 kWe, fission power systems become an attractive technology offering a scalable modular design of the reactor, shield, power conversion, and heat transport subsystems. Near term emphasis has been placed in the 1-10kWe range that lies outside realistic radioisotope power levels and fills a promising technology gap capable of enabling both science and human exploration missions. History has shown that development of space reactors is technically, politically, and financially challenging and requires a new approach to their design and development. A small team of NASA and DOE experts are providing a solution to these enabling FPS technologies starting with the lowest power and most cost effective reactor series named Kilopower that is scalable from approximately 1-10 kWe.

  12. Monitoring and diagnostic system of fission product transport and release in nuclear power plants

    International Nuclear Information System (INIS)

    Kodaira, H.; Kondo, S.; Togo, Y.

    1983-01-01

    A monitoring and diagnostic system (MADS) of fission product (FP) transport and release in nuclear power plants (NPPs) is proposed and the conceptual design for MADS is studied. A MADS can be described in the most general way as a computer-based information processing system which takes in plant data, processes it and displays the results to the NPP's operating crew. A major concern for MADS is, however, not to evaluate general plant dynamics, but to monitor the distribution of whole radioactive materials such as FP, and to diagnose the plant state in the view of FP transport during the NPP's lifetime. Several functions demanded of MADS are: (a) during normal operation, to certify the fuel integrity and the effectiveness of the purification systems, (b) in an unusual event, to identify the event and to monitor the amount of FP release with accuracy, and (c) in case of a rare occurrence, to estimate the maximum potential release

  13. Design of a Mechanical NaK Pump for Fission Space Power

    Science.gov (United States)

    Mireles, Omar R.; Bradley, David E.; Godfroy, Thomas

    2011-01-01

    Alkali liquid metal cooled fission reactor concepts are under development for spaceflight power requirements. One such concept utilizes a sodium-potassium eutectic (NaK) as the primary loop working fluid, which has specific pumping requirements. Traditionally, electromagnetic linear induction pumps have been used to provide the required flow and pressure head conditions for NaK systems but they can be limited in performance, efficiency, and number of available vendors. The objective of the project was to develop a mechanical NaK centrifugal pump that takes advantages of technology advances not available in previous liquid metal mechanical pump designs. This paper details the design, build, and performance test of a mechanical NaK pump developed at NASA Marshall Space Flight Center. The pump was designed to meet reactor cooling requirements using commercially available components modified for high temperature NaK service.

  14. Fission gas behaviour modelling in plate fuel during a power transient

    International Nuclear Information System (INIS)

    Portier, S.

    2003-01-01

    This thesis is dedicated to the identification and modelization of the phenomena which are at the origin of the release of the fission gas formed in UO 2 plate fuels during the irradiation in a power transient. In the first experimental part, samples of plate fuels, irradiated at 36 GWj/tU, have been annealed to temperatures from 1100 C to 1500 C in a device that enabled the measurement of gas release in real time. At 1300 C, post-annealing observations demonstrated a link between the measured gas releases to a rapid formation of labyrinths at the grain surface. These labyrinths, which were formed by intergranular bubble interconnection, create release paths for the gas atoms which reach the grain surface. At this stage, the available experimental results (annealing and observations) were interpreted considering that it is the spreading of the gas atoms from the grains to the grain boundaries that is at the origin of the observed releases. This interpretation generates the hypothesis that a) at the end of the basic irradiation, the gas is at the atomic state and b) during the annealing, the spreading is reduced by the intragranular bubbles of the gas atoms. The last part of the work is dedicated to the modelization of the main phenomena at the origin of the gas release. The model developed, based on the model of the gas behaviour in MARGARET PWR, highlighted the great influence of the irradiation conditions on the gas distribution at the end of the irradiation and also its influence on the fission gas release during the power transient. (author) [fr

  15. Research problems of fission product behaviour in fuels of nuclear power plants and ways of their solution

    International Nuclear Information System (INIS)

    Sulaberidze, V.Sh.

    1988-01-01

    The most important problems of studying behaviour of fission products in fuel elements of maneouvrable nuclear power plants units are formulated. In-pile and out-of-pile investigation methods solving these problems are characterized in brief. 12 refs.; 2 figs

  16. Birth to death analysis of the energy payback ratio and CO2 gas emission rates from coal, fission, wind, and DT-fusion electrical power plants

    International Nuclear Information System (INIS)

    White, Scott W.; Kulcinski, Gerald L.

    2000-01-01

    The amount of electrical energy produced over the lifetime of coal, LWR fission, UP fusion, and wind power plants is compared to the total amount of energy required to procure the fuel, build, operate, and decommission the power plants. The energy payback ratio varies from a low of 11 for coal plants to a high of 27 for DT-fusion plants. The magnitude of the energy investment and the source of the various energy inputs determine the CO 2 emission factor. This number varies from a low of 9 to a high of 974 tonnes of CO 2 per GW e h for DT-fusion and coal plants, respectively

  17. Design and Test Plans for a Non-Nuclear Fission Power System Technology Demonstration Unit

    Science.gov (United States)

    Mason, Lee; Palac, Donald; Gibson, Marc; Houts, Michael; Warren, John; Werner, James; Poston, David; Qualls, Arthur Lou; Radel, Ross; Harlow, Scott

    2012-01-01

    A joint National Aeronautics and Space Administration (NASA) and Department of Energy (DOE) team is developing concepts and technologies for affordable nuclear Fission Power Systems (FPSs) to support future exploration missions. A key deliverable is the Technology Demonstration Unit (TDU). The TDU will assemble the major elements of a notional FPS with a non-nuclear reactor simulator (Rx Sim) and demonstrate system-level performance in thermal vacuum. The Rx Sim includes an electrical resistance heat source and a liquid metal heat transport loop that simulates the reactor thermal interface and expected dynamic response. A power conversion unit (PCU) generates electric power utilizing the liquid metal heat source and rejects waste heat to a heat rejection system (HRS). The HRS includes a pumped water heat removal loop coupled to radiator panels suspended in the thermal-vacuum facility. The basic test plan is to subject the system to realistic operating conditions and gather data to evaluate performance sensitivity, control stability, and response characteristics. Upon completion of the testing, the technology is expected to satisfy the requirements for Technology Readiness Level 6 (System Demonstration in an Operational and Relevant Environment) based on the use of high-fidelity hardware and prototypic software tested under realistic conditions and correlated with analytical predictions.

  18. Fission products collecting devices

    International Nuclear Information System (INIS)

    Matsumoto, Hiroshi

    1979-01-01

    Purpose: To enable fission products trap with no contamination to coolants and cover gas by the provision of a fission products trap above the upper part of a nuclear power plant. Constitution: Upon fuel failures in a reactor core, nuclear fission products leak into coolants and move along the flow of the coolants to the coolants above the reactor core. The fission products are collected in a trap container and guided along a pipeline into fission products detector. The fission products detector monitors the concentration of the fission products and opens the downstream valve of the detector when a predetermined concentration of the fission products is detected to introduce the fission products into a waste gas processing device and release them through the exhaust pipe. (Seki, T.)

  19. Needs and accuracy requirements for fission product nuclear data in the physics design of power reactor cores

    International Nuclear Information System (INIS)

    Rowlands, J.L.

    1978-01-01

    The fission product nuclear data accuracy requirements for fast and thermal reactor core performance predictions were reviewed by Tyror at the Bologna FPND Meeting. The status of the data was assessed at the Meeting and it was concluded that the requirements of thermal reactors were largely met, and the yield data requirements of fast reactors, but not the cross section requirements, were met. However, the World Request List for Nuclear Data (WRENDA) contains a number of requests for fission product capture cross sections in the energy range of interest for thermal reactors. Recent reports indicate that the fast reactor reactivity requirements might have been met by integral measurements made in zero power critical assemblies. However, there are requests for the differential cross sections of the individual isotopes to be determined in addition to the integral data requirements. The fast reactor requirements are reviewed, taking into account some more recent studies of the effects of fission products. The sodium void reactivity effect depends on the fission product cross sections in a different way to the fission product reactivity effect in a normal core. This requirement might call for different types of measurement. There is currently an interest in high burnup fuel cycles and alternative fuel cycles. These might require more accurate fission product data, data for individual isotopes and data for capture products. Recent calculations of the time dependence of fission product reactivity effects show that this is dependent upon the data set used and there are significant uncertainties. Some recent thermal reactor studies on approximations in the treatment of decay chains and the importance of xenon and samarium poisoning are also summarized. (author)

  20. How much of the rocks and the oceans for power? Exploiting the uranium-thorium fission cycle

    International Nuclear Information System (INIS)

    Lewis, W.B.

    1964-04-01

    Even at quite low costs there appear to be many routes available to supply the world population of the future with its power for electricity, heat, energy storage, portable fuel, desalting water and local climate control. For example, sufficient power could come from nuclear fission in thermal neutron reactors. When rich uranium ores have become scarce, the price will rise from the current $13/kg U, but with improved techniques of extraction and the choice of an economical fuel cycle, abundant uranium for many centuries appears to be available in the rocks and the oceans. Even from reactors already developed to the stage of engineering design it is possible to choose a fuel cycle to which uranium at $250/kg U would contribute no more than 2 mill/kWh. Without suggesting when such a high cost might he reached, its implications are examined. The optimum fuel cycle would balance the financing charges on the fuel inventory and the costs of fuel make-up supply and reprocessing. By using uranium and thorium in combination at least 50,000 MWd can be derived per tonne of uranium. At a current low net conversion efficiency of 30% and an overall rating of 6 thermal kW/kg, the natural uranium inventory would cost at the suggested high price $250/(6 x 0.3) $139/ekW and for 7000 hr/yr at 7% annual charges would contribute 1.4 mill/ekWh. At 50 MWd/kg U the make-up supply contributes 250/(50 x 24 x 0.3) = 0.7 mill/ekWh. Probably higher efficiency and possibly higher specific power ratings would be used to lower such costs. The value of uranium is related to its content of the fissile U-235, and even though most power may be derived from thorium, its value will not rise comparably with that of uranium. In the course of time a ceiling will be set on the value of fissile material by the introduction of processes other than the thermal neutron fission chain reaction for producing power or neutrons. The total cost of nuclear power includes also contributions from the cost of equipment

  1. How much of the rocks and the oceans for power? Exploiting the uranium-thorium fission cycle

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, W B

    1964-04-15

    Even at quite low costs there appear to be many routes available to supply the world population of the future with its power for electricity, heat, energy storage, portable fuel, desalting water and local climate control. For example, sufficient power could come from nuclear fission in thermal neutron reactors. When rich uranium ores have become scarce, the price will rise from the current $13/kg U, but with improved techniques of extraction and the choice of an economical fuel cycle, abundant uranium for many centuries appears to be available in the rocks and the oceans. Even from reactors already developed to the stage of engineering design it is possible to choose a fuel cycle to which uranium at $250/kg U would contribute no more than 2 mill/kWh. Without suggesting when such a high cost might be reached, its implications are examined. The optimum fuel cycle would balance the financing charges on the fuel inventory and the costs of fuel make-up supply and reprocessing. By using uranium and thorium in combination at least 50,000 MWd can be derived per tonne of uranium. At a current low net conversion efficiency of 30% and an overall rating of 6 thermal kW/kg, the natural uranium inventory would cost at the suggested high price $250/(6 x 0.3) $139/ekW and for 7000 hr/yr at 7% annual charges would contribute 1.4 mill/ekWh. At 50 MWd/kg U the make-up supply contributes 250/(50 x 24 x 0.3) = 0.7 mill/ekWh. Probably higher efficiency and possibly higher specific power ratings would be used to lower such costs. The value of uranium is related to its content of the fissile U-235, and even though most power may be derived from thorium, its value will not rise comparably with that of uranium. In the course of time a ceiling will be set on the value of fissile material by the introduction of processes other than the thermal neutron fission chain reaction for producing power or neutrons. The total cost of nuclear power includes also contributions from the cost of equipment

  2. Feasibility study of a small, thorium-based fission power system for space and terrestrial applications

    Science.gov (United States)

    Worrall, Michael Jason

    One of the current challenges facing space exploration is the creation of a power source capable of providing useful energy for the entire duration of a mission. Historically, radioisotope batteries have been used to provide load power, but this conventional system may not be capable of sustaining continuous power for longer duration missions. To remedy this, many forays into nuclear powered spacecraft have been investigated, but no robust system for long-term power generation has been found. In this study, a novel spin on the traditional fission power system that represents a potential optimum solution is presented. By utilizing mature High Temperature Gas Reactor (HTGR) technology in conjunction with the capabilities of the thorium fuel cycle, we have created a light-weight, long-term power source capable of a continuous electric power output of up to 70kW for over 15 years. This system relies upon a combination of fissile, highly-enriched uranium dioxide and fertile thorium carbide Tri-Structural Isotropic (TRISO) fuel particles embedded in a hexagonal beryllium oxide matrix. As the primary fissile material is consumed, the fertile material breeds new fissile material leading to more steady fuel loading over the lifetime of the core. Reactor control is achieved through an innovative approach to the conventional boron carbide neutron absorber by utilizing sections of borated aluminum placed in rotating control drums within the reflector. Borated aluminum allows for much smaller boron concentrations, thus eliminating the potential for 10B(n,alpha)6Li heating issues that are common in boron carbide systems. A wide range of other reactivity control systems are also investigated, such as a radially-split rotating reflector. Lastly, an extension of the design to a terrestrial based system is investigated. In this system, uranium enrichment is dropped to 20 percent in order to meet current regulations, a solid uranium-zirconium hydride fissile driver replaces the

  3. Materials-of-Construction Radiation Sensitivity for a Fission Surface Power Convertor

    Science.gov (United States)

    Bowman, Cheryl L.; Geng, Steven M.; Niedra, Janis M.; Sayir, Ali; Shin, Eugene E.; Sutter, James K.; Thieme, Lanny G.

    2007-01-01

    A fission reactor combined with a free-piston Stirling convertor is one of many credible approaches for producing electrical power in space applications. This study assumes dual-opposed free-piston Stirling engines/linear alternators that will operate nominally at 825 K hot-end and 425 K cold-end temperatures. The baseline design options, temperature profiles, and materials of construction discussed here are based on historical designs as well as modern convertors operating at lower power levels. This notional design indicates convertors primarily made of metallic components that experience minimal change in mechanical properties for fast neutron fluences less than 10(sup 20) neutrons per square centimeter. However, these radiation effects can impact the magnetic and electrical properties of metals at much lower fluences than are crucial for mechanical property integrity. Moreover, a variety of polymeric materials are also used in common free-piston Stirling designs for bonding, seals, lubrication, insulation and others. Polymers can be affected adversely by radiation doses as low as 10(sup 5) - 10(sup 10) rad. Additionally, the absorbing dose rate, radiation hardness, and the resulting effect (either hardening or softening) varies depending on the nature of the particular polymer. The classes of polymers currently used in convertor fabrication are discussed along possible substitution options. Thus, the materials of construction of prototypic Stirling convertor engines have been considered and the component materials susceptible to damage at the lowest neutron fluences have been identified.

  4. Comparative uptake of gamma-emitting fission product nuclides by plants

    International Nuclear Information System (INIS)

    D'souza, T.J.; Mistry, K.B.

    1974-01-01

    The comparative uptake of long-lived gamma-emitting fission product nuclides 106 Ru, 125 Sb, 137 Cs and 144 Ce, present in global fallout from nuclear explosions, by maize (Zea mays L) plants was examined in water culture experiments. Over identical duration of plant growth, the extent of accumulation of the radionuclides in aerial tissues was in the following decreasing order: 137 Cs >, 125 Sb >, 106 Ru > and 144 Ce. In roots, however, the retention of 144 Ce and 106 Ru was greater than that of 137 Cs and 125 Sb. Complementary studies with maize and rice (Oryza sativa L) grown on two contrasting soil types, namely, laterite and black clay loam indicated that 137 Cs uptake by plants was markedly greater than that of the other radionuclides in both soil types. Plant uptake of 106 Ru and 125 Sb was significantly higher than that of 144 Ce in the black soil. In the laterite, however, 144 Ce uptake far exceeded that of 106 Ru and 125 Sb. In general, maize removed higher amounts of the radionuclides than rice from both soil types. (author)

  5. Two-Step Multi-Physics Analysis of an Annular Linear Induction Pump for Fission Power Systems

    Science.gov (United States)

    Geng, Steven M.; Reid, Terry V.

    2016-01-01

    One of the key technologies associated with fission power systems (FPS) is the annular linear induction pump (ALIP). ALIPs are used to circulate liquid-metal fluid for transporting thermal energy from the nuclear reactor to the power conversion device. ALIPs designed and built to date for FPS project applications have not performed up to expectations. A unique, two-step approach was taken toward the multi-physics examination of an ALIP using ANSYS Maxwell 3D and Fluent. This multi-physics approach was developed so that engineers could investigate design variations that might improve pump performance. Of interest was to determine if simple geometric modifications could be made to the ALIP components with the goal of increasing the Lorentz forces acting on the liquid-metal fluid, which in turn would increase pumping capacity. The multi-physics model first calculates the Lorentz forces acting on the liquid metal fluid in the ALIP annulus. These forces are then used in a computational fluid dynamics simulation as (a) internal boundary conditions and (b) source functions in the momentum equations within the Navier-Stokes equations. The end result of the two-step analysis is a predicted pump pressure rise that can be compared with experimental data.

  6. Solid State Track Recorder fission rate measurements in low power light water reactor pressure vessel mockups

    International Nuclear Information System (INIS)

    Ruddy, F.H.; Roberts, J.H.; Kellogg, L.S.

    1985-01-01

    The results of extensive SSTR measurements made at the Pool Critical Assembly (PCA) facility at Oak Ridge National Laboratory have been reported previously. Measurements were made at key locations in PCA which is an idealized mockup of the water gap, thermal shield, pressure vessel geometry of a light water reactor. Recently, additional SSTR fission rate measurements have been carried out for 237-Np, 238-U, and 235-U in key locations in the NESTOR Shielding and Dosimetry Improvement Program (NESDIP) mockup facility located at Winfrith, England. NESDIP is a replica of the PCA facility, and comparisons will be made between PCA and NESDIP measurements. The results of measurements made at the engineering mockup at the VENUS critical assembly at CEN/SCK, Mol, Belgium will also be reported. Measurements were made at selected radial and azimuthal locations in VENUS, which models the in-core and near-core regions of a pressurized water reactor. Comparisons of absolute SSTR fission rates with absolute fission rates made with the Mol miniature fission chamber will be reported. Absolute fission rate comparisons have also been made between the NBS fission chamber, radiometric fission foils, and SSTRs, and these results will be summarized

  7. Preliminary assessment of a symbiotic fusion--fission power system using the TH/U refresh fuel cycle

    International Nuclear Information System (INIS)

    Bender, D.J.; Lee, J.D.; Moir, R.W.

    1977-10-01

    Studies of the mirror hybrid reactor by LLL/GA have concluded that the most promising role for this reactor concept is that of a producer of fissile fuel for fission reactors. Studies to date have examined primarily the U/Pu fuel cycle with light-water reactors serving as the consumers of the hybrid-bred fissile fuel; the specific scenarios examined required reprocessing and refabrication of the bred fuel before introduction into the fission reactor. This combination of technologies was chosen to illustrate the manner in which the hybrid reactor concept could serve the needs of, and use the technology of, the fission reactor industry as it now exists (and as it was thought it would evolve). However, the current U.S. Administration has expressed strong concerns about proliferation of nuclear weapons capability and terrorist diversion of weapons-grade nuclear materials. These concerns are based on the projected technology for the light-water reactor/fast breeder reactor using the U/Pu fuel cycle and extensive reprocessing/refabrication. A symbiotic nuclear power generation concept (hybrid fissile producer plus fission burner reactors) is described which eliminates those aspects of the present nuclear fuel cycle that (may) represent significant proliferation/diversion risks. Specifically, the proposed concept incorporates the following features: (1)Th/U 233 fuel cycle, (2) no reprocessing or fabrication of fissile material, and (3) no fissile material in a weapons-grade state

  8. Comparison of nuclear irradiation parameters of fusion breeder materials in high flux fission test reactors and a fusion power demonstration reactor

    International Nuclear Information System (INIS)

    Fischer, U.; Herring, S.; Hogenbirk, A.; Leichtle, D.; Nagao, Y.; Pijlgroms, B.J.; Ying, A.

    2000-01-01

    Nuclear irradiation parameters relevant to displacement damage and burn-up of the breeder materials Li 2 O, Li 4 SiO 4 and Li 2 TiO 3 have been evaluated and compared for a fusion power demonstration reactor and the high flux fission test reactor (HFR), Petten, the advanced test reactor (ATR, INEL) and the Japanese material test reactor (JMTR, JAERI). Based on detailed nuclear reactor calculations with the MCNP Monte Carlo code and binary collision approximation (BCA) computer simulations of the displacement damage in the polyatomic lattices with MARLOWE, it has been investigated how well the considered HFRs can meet the requirements for a fusion power reactor relevant irradiation. It is shown that a breeder material irradiation in these fission test reactors is well suited in this regard when the neutron spectrum is well tailored and the 6 Li-enrichment is properly chosen. Requirements for the relevant nuclear irradiation parameters such as the displacement damage accumulation, the lithium burn-up and the damage production function W(T) can be met when taking into account these prerequisites. Irradiation times in the order of 2-3 full power years are necessary for the HFR to achieve the peak values of the considered fusion power Demo reactor blanket with regard to the burn-up and, at the same time, the dpa accumulation

  9. Study of advanced fission power reactor development for the United States. Volume II

    International Nuclear Information System (INIS)

    1976-01-01

    This report presents the results of a multi-phase research study which had as its objective the comparative study of various advanced fission reactors and evaluation of alternate strategies for their development in the USA through the year 2020. By direction from NSF, ''advanced'' reactors were defined as those which met the dual requirements of (1) offering a significant improvement in fissile fuel utilization as compared to light-water reactors and (2) currently receiving U.S. Government funding. (A detailed study of the LMFBR was specifically excluded, but cursory baseline data were obtained from ERDA sources.) Included initially were the High-Temperature Gas-Cooled Reactor (HTGR), Gas-Cooled Fast Reactor (GCFR), Molten Salt Reactor (MSR), and Light-Water Breeder Reactor (LWBR). Subsequently, the CANDU Heavy Water Reactor (HWR) was included for comparison due to increased interest in its potential. This volume presents the reasoning process and analytical methods utilized to arrive at the conclusions for the overall study

  10. Siting of Nuclear Power Plants in Metropolitan Areas. Estimation of Population Doses due to Accidental Release of Fission Products

    Energy Technology Data Exchange (ETDEWEB)

    Bresser, H. [Technischer Ueberwachungs-Verein Rheinland E.V., Cologne (Germany); Schwarzer, W. [Institut fuer Reaktorsicherheit der Technischen Ueberwachungs-Vereine E.V., Cologne (Germany)

    1967-09-15

    The safety of large nuclear power plants in heavily populated areas depends entirely on engineered safeguards. An assessment of their reliability and effectiveness will have to play a major role in any safety analysis of such a plant, and this assessment will have to be made on the basis of the radiological burden to the environment - in terms of individual dose and a population dose - which can be accepted as tolerable in case of a severe accident. The calculation of the dispersion of fission products in the atmosphere, which links the radiological burden to the release of radioactivity, should be modified. The fact that distance factors, aside from a comparably small exclusion area, can no longer be taken into account suggests the introduction of the parameter ''population density'' and an extensive use of the man-rem concept. In this connection the time history of the release and the influence of variations of wind directions lose their importance. The authors have carried out calculations of the population dose, which could be received in a metropolitan area as a consequence of a severe reactor accident, using population densities, height of release above ground and generalized meteorological data as the main parameters. The results of these calculations are used as a basis for an assessment of the performance requirements of the engineered safeguards system, and the relative importance of different components of this system is discussed. (author)

  11. Free-Piston Stirling Power Conversion Unit for Fission Power System, Phase II Final Report

    Science.gov (United States)

    Wood, J. Gary; Stanley, John

    2016-01-01

    In Phase II, the manufacture and testing of two 6-kW(sub e)Stirling engines was completed. The engines were delivered in an opposed 12-kW(sub e) arrangement with a common expansion space heater head. As described in the Phase I report, the engines were designed to be sealed both hermetically and with a bolted O-ring seal. The completed Phase II convertor is in the bolted configuration to allow future disassembly. By the end of Phase II, the convertor had passed all of the final testing requirements in preparation for delivery to the NASA Glenn Research Center. The electronic controller also was fabricated and tested during Phase II. The controller sets both piston amplitudes and maintains the phasing between them. It also sets the operating frequency of the machine. Details of the controller are described in the Phase I final report. Fabrication of the direct-current to direct-current (DC-DC) output stage, which would have stepped down the main controller output voltage from 700 to 120 V(sub DC), was omitted from this phase of the project for budgetary reasons. However, the main controller was successfully built, tested with the engines, and delivered. We experienced very few development issues with this high-power controller. The project extended significantly longer than originally planned because of yearly funding delays. The team also experienced several hardware difficulties along the development path. Most of these were related to the different thermal expansions of adjacent parts constructed of different materials. This issue was made worse by the large size of the machine. Thermal expansion problems also caused difficulties in the brazing of the opposed stainless steel sodium-potassium (NaK) heater head. Despite repeated attempts Sunpower was not able to successfully braze the opposed head under this project. Near the end of the project, Glenn fabricated an opposed Inconel NaK head, which was installed prior to delivery for testing at Glenn. Engine

  12. Construction of the first compendium of chemical-genetic profiles in the fission yeast Schizosaccharomyces pombe and comparative compendium approach

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sangjo [Bioinformatics Lab, Healthcare Group, SK Telecom, 9-1, Sunae-dong, Pundang-gu, Sungnam-si, Kyunggi-do 463-784 (Korea, Republic of); Lee, Minho [Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Chang, Hyeshik [Department of Biological Science, Seoul National University, 599 Gwanakro, Gwanak-gu, Seoul 151-747 (Korea, Republic of); Nam, Miyoung [Department of New Drug Discovery and Development, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 305-764 (Korea, Republic of); Park, Han-Oh [Bioneer Corp., 8-11 Munpyeongseo-ro, Daedeok-gu, Daejeon 306-220 (Korea, Republic of); Kwak, Youn-Sig [Department of Applied Biology, Gyeongsang National University, 501 Jinju-daero, Jinju, Gyeongnam 660-701 (Korea, Republic of); Ha, Hye-jeong [Aging Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-Gu, Daejeon 305-806 (Korea, Republic of); Kim, Dongsup [Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Hwang, Sung-Ook [Department of Obstetrics and Gynecology, Inha University Hospital, 7-206 Sinheung-dong, Jung-gu, Incheon 400-711 (Korea, Republic of); Hoe, Kwang-Lae [Department of New Drug Discovery and Development, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 305-764 (Korea, Republic of); Kim, Dong-Uk [Aging Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-Gu, Daejeon 305-806 (Korea, Republic of)

    2013-07-12

    Highlights: •The first compendium of chemical-genetic profiles form fission yeast was generated. •The first HTS of drug mode-of-action in fission yeast was performed. •The first comparative chemical genetic analysis between two yeasts was conducted. -- Abstract: Genome-wide chemical genetic profiles in Saccharomyces cerevisiae since the budding yeast deletion library construction have been successfully used to reveal unknown mode-of-actions of drugs. Here, we introduce comparative approach to infer drug target proteins more accurately using two compendiums of chemical-genetic profiles from the budding yeast S. cerevisiae and the fission yeast Schizosaccharomyces pombe. For the first time, we established DNA-chip based growth defect measurement of genome-wide deletion strains of S. pombe, and then applied 47 drugs to the pooled heterozygous deletion strains to generate chemical-genetic profiles in S. pombe. In our approach, putative drug targets were inferred from strains hypersensitive to given drugs by analyzing S. pombe and S. cerevisiae compendiums. Notably, many evidences in the literature revealed that the inferred target genes of fungicide and bactericide identified by such comparative approach are in fact the direct targets. Furthermore, by filtering out the genes with no essentiality, the multi-drug sensitivity genes, and the genes with less eukaryotic conservation, we created a set of drug target gene candidates that are expected to be directly affected by a given drug in human cells. Our study demonstrated that it is highly beneficial to construct the multiple compendiums of chemical genetic profiles using many different species. The fission yeast chemical-genetic compendium is available at (http://pombe.kaist.ac.kr/compendium)

  13. Testing of an Annular Linear Induction Pump for the Fission Surface Power Technology Demonstration Unit

    Science.gov (United States)

    Polzin, K. A.; Pearson, J. B.; Webster, K.; Godfoy, T. J.; Bossard, J. A.

    2013-01-01

    Results of performance testing of an annular linear induction pump that has been designed for integration into a fission surface power technology demonstration unit are presented. The pump electromagnetically pushes liquid metal (NaK) through a specially-designed apparatus that permits quantification of pump performance over a range of operating conditions. Testing was conducted for frequencies of 40, 55, and 70 Hz, liquid metal temperatures of 125, 325, and 525 C, and input voltages from 30 to 120 V. Pump performance spanned a range of flow rates from roughly 0.3 to 3.1 L/s (4.8 to 49 gpm), and pressure heads of <1 to 104 kPa (<0.15 to 15 psi). The maximum efficiency measured during testing was 5.4%. At the technology demonstration unit operating temperature of 525 C the pump operated over a narrower envelope, with flow rates from 0.3 to 2.75 L/s (4.8 to 43.6 gpm), developed pressure heads from <1 to 55 kPa (<0.15 to 8 psi), and a maximum efficiency of 3.5%. The pump was supplied with three-phase power at 40 and 55 Hz using a variable-frequency motor drive, while power at 55 and 70 Hz was supplied using a variable-frequency power supply. Measured performance of the pump at 55 Hz using either supply exhibited good quantitative agreement. For a given temperature, the peak in efficiency occurred at different flow rates as the frequency was changed, but the maximum value of efficiency was relative insensitive within 0.3% over the frequency range tested, including a scan from 45 to 78 Hz. The objectives of the FSP technology project are as follows:5 • Develop FSP concepts that meet expected surface power requirements at reasonable cost with added benefits over other options. • Establish a nonnuclear hardware-based technical foundation for FSP design concepts to reduce overall development risk. • Reduce the cost uncertainties for FSP and establish greater credibility for flight system cost estimates. • Generate the key nonnuclear products to allow Agency

  14. Polarographic determination of Iodide and Iodate, in Solutions Coming from Aerosols in Fission Products Containment Studies in Nuclear Power Stations

    International Nuclear Information System (INIS)

    Sanchez, M.; Ballesteros, O.; Fernandez, M.; Clavero, M.A.; Gonzalez, A.M.

    2000-01-01

    A polarographic method is described for the iodine species determination, iodide and iodate in water solutions. the iodate can be determined by differential pulse polarography. Calibration curves and the detection and determination limits have been obtained. Iodides is oxidized to iodate with sodium hypochlorite and the excess of oxidizing agent is destroyed with sodium sulphide. The concentration of iodide is calculated as the difference between the concentration of iodate in the sample before and after the oxidation. As an application, species of iodine in samples coming from the experimental plants GIRS (Gaseous Iodine Removal by Sprays) of Nuclear Fission Department of the CIEMAT, dedicated to fission products containment studies in nuclear power station, were determined. (Author) 10 refs

  15. Status of the Development of Low Cost Radiator for Surface Fission Power - II

    Science.gov (United States)

    Tarau, Calin; Maxwell, Taylor; Anderson, William G.; Wagner, Corey; Wrosch, Matthew; Briggs, Maxwell H.

    2016-01-01

    NASA Glenn Research Center (GRC) is developing fission power system technology for future Lunar and Martian surface power applications. The systems are envisioned in the 10 to 100kWe range and have an anticipated design life of 8 to 15 years with no maintenance. NASA GRC is currently setting up a 55 kWe non-nuclear system ground test in thermal-vacuum to validate technologies required to transfer reactor heat, convert the heat into electricity, reject waste heat, process the electrical output, and demonstrate overall system performance. The paper reports on the development of the heat pipe radiator to reject the waste heat from the Stirling convertors. Reducing the radiator mass, size, and cost is essential to the success of the program. To meet these goals, Advanced Cooling Technologies, Inc. (ACT) and Vanguard Space Technologies, Inc. (VST) are developing a single facesheet radiator with heat pipes directly bonded to the facesheet. The facesheet material is a graphite fiber reinforced composite (GFRC) and the heat pipes are titanium/water Variable Conductance Heat Pipes (VCHPs). By directly bonding a single facesheet to the heat pipes, several heavy and expensive components can be eliminated from the traditional radiator design such as, POCO"TM" foam saddles, aluminum honeycomb, and a second facesheet. As mentioned in previous papers by the authors, the final design of the waste heat radiator is described as being modular with independent GFRC panels for each heat pipe. The present paper reports on test results for a single radiator module as well as a radiator cluster consisting of eight integral modules. These tests were carried out in both ambient and vacuum conditions. While the vacuum testing of the single radiator module was performed in the ACT's vacuum chamber, the vacuum testing of the eight heat pipe radiator cluster took place in NASA GRC's vacuum chamber to accommodate the larger size of the cluster. The results for both articles show good agreement

  16. Fission product release measured during fuel damage tests at the Power Burst Facility

    International Nuclear Information System (INIS)

    Osetek, D.J.; Hartwell, J.K.; Vinjamuri, K.; Cronenberg, A.W.

    1985-01-01

    Results are presented of fission product release behavior observed during four severe fuel damage tests on bundles of UO 2 fuel rods. Transient temperatures up to fuel melting were obtained in the tests that included both rapid quench and slow cooldown, low and high (36 GWd/t) burnup fuel and the addition of Ag-In-Cd control rods. Release fractions of major fission product species and release rates of noble gas species are reported. Significant differences in release behavior are discussed between heatup and cooldown periods, low and high burnup fuel and long- and short-lived fission products. Explanations are offered for the probable reasons for the observed differences and recommendations for further studies are given

  17. TMI-2 decay power: LASL fission-product and actinide decay power calculations for the President's commission on the accident at Three Mile Island

    International Nuclear Information System (INIS)

    England, T.R.; Wilson, W.B.

    1980-03-01

    Fission-product and actinide decay heating, gas content, curies, and detailed contributions of the most important nuclide contributors were supplied in a series of letters following requests from the Presidential Commission on the Accident at Three Mile Island. In addition, similar data assuming different irradiation (power) histories were requested for purposes of comparison. This report consolidates the tabular and graphical data supplied and explains its basis

  18. TMI-2 decay power: LASL fission-product and actinide decay power calculations for the President's Commission at Three Mile Island

    Energy Technology Data Exchange (ETDEWEB)

    England, T.R.; Wilson, W.B.

    1979-10-01

    Fission-product and actinide decay heating, gas content, curies, and detailed contributions of the most important nuclide contributors were supplied in a series of letters following requests from the Presidential Commission on the Accident at Three Mile Island. In addition, similar data assuming different irradiation (power) histories were requested for purposes of comparison. This report consolidates the tabular and graphical data supplied and explains its basis.

  19. TMI-2 decay power: LASL fission-product and actinide decay power calculations for the President's Commission at Three Mile Island

    International Nuclear Information System (INIS)

    England, T.R.; Wilson, W.B.

    1979-10-01

    Fission-product and actinide decay heating, gas content, curies, and detailed contributions of the most important nuclide contributors were supplied in a series of letters following requests from the Presidential Commission on the Accident at Three Mile Island. In addition, similar data assuming different irradiation (power) histories were requested for purposes of comparison. This report consolidates the tabular and graphical data supplied and explains its basis

  20. A comparative analysis of the effect of gaseous fission products release on the thermal behaviour of oxide fuel rods

    International Nuclear Information System (INIS)

    Totev, T.L.; Kolev, I.G.

    1992-01-01

    Four different models of gaseous fission product release are compared in order to assess the relative effect of thermal characteristics of the fuel rods. The results show that the use of Weisman and EPRI models at a high burnup (over 50000 MW.d/tU) leads to almost the same figures of maximum fuel temperature and gas gap thermal conductivity. The use of Beyer-Hann (Betelle) and Pazdera-Valach (Rzez) models leads to under prediction of the fuel element thermal characteristics. A conclusion has been made that the Weisman model is the most suitable for the WWER-type fuel elements behaviour prediction. 10 refs., 7 figs

  1. Fission - track age of the Marjalahti Pallasite

    International Nuclear Information System (INIS)

    Bondar, Yu.V.; Perelygin, V.P.

    2006-01-01

    Full text: Investigation of fossil charged-particle tracks in various mineral phases of extraterrestrial samples is a powerful method for research the early stages of the solar system. Over geological time, meteorites crystals have accumulated a record of tracks produced by heavily charged energetic particles from both internal (spontaneous fission of 238U and some other extinct isotopes) and external sources (galactic cosmic rays with Z>20). The fortunate fact that meteorite grains can accumulate latent and very long-lived tracks since soon after the end of nucleosynthesis in the solar nebula enables one to decode their radiation history and to detect any thermal events in the meteorite cosmic history by revealing these tracks through suitable etching procedures. Only a few minerals in meteorites (mainly phosphates) contain small amount of uranium; the fact that 238 U undergoes fission with fission-decay constant λ f ∼ 8.2x10 -17 yr -1 allows one to use this isotope as a chronometer. By measuring the U concentration in the crystals (by reactor irradiation) and the density of the spontaneous-fission tracks it is relatively easy to calculate the 'fission-track age' if 238 U is the main source of fission tracks. However the fission-track dating of extraterrestrial samples compared with the terrestrial ones has some peculiar features due to presence of a number of other potential track sources except the spontaneous fission of 238 U, such as the spontaneous fission of presently extinct 244 Pu, heavy nuclei of cosmic rays and induced fission by cosmic ray primaries. Only tracks from the spontaneous fission of U and Pu are suitable for fission-track dating. The competing effects of these fissioning elements, whose half-lives differ by a factor of ∼50, form a basis for a fission-track chronology for samples older than ∼ 4.0 Gyr. Over small intervals in time (∼ few x10 8 yr ) the track density from spontaneous fission of 238 U is nearly constant. However, the

  2. Future developments of power supply from nuclear fission and fusion until the middle of the 21st century

    International Nuclear Information System (INIS)

    1987-03-01

    The purpose of this study made by General Technology Systems (Netherlands) is to provide information about nuclear fission and fusion as methods for power generation, with which, in the framework of a study into the possibilities of durable energy sources, choices may be made from the various possibilities for future energy supply. The physical processes upon which the power generation relies are treated briefly. The technologies employed are discussed together with their changes and improvements, now and in the future, and the economic factors by which they are accompanied. How much of this energy will be used in the Netherlands, is discussed. In order to know the opinion of others about these subjects the dealers of the current nuclear power stations were asked to give their opinions which are collected in a supplement. 166 refs.; 18 figs.; 19 tabs

  3. Advances on fission chamber modelling

    International Nuclear Information System (INIS)

    Filliatre, Philippe; Jammes, Christian; Geslot, Benoit; Veenhof, Rob

    2013-06-01

    In-vessel, online neutron flux measurements are routinely performed in mock-up and material testing reactors by fission chambers. Those measurements have a wide range of applications, including characterization of experimental conditions, reactor monitoring and safety. Depending on the application, detectors may experience a wide range of constraints, of several magnitudes, in term of neutron flux, gamma-ray flux, temperature. Hence, designing a specific fission chamber and measuring chain for a given application is a demanding task. It can be achieved by a combination of experimental feedback and simulating tools, the latter being based on a comprehensive understanding of the underlying physics. A computation route that simulates fission chambers, named CHESTER, is presented. The retrieved quantities of interest are the neutron-induced charge spectrum, the electronic and ionic pulses, the mean current and variance, the power spectrum. It relies on the GARFIELD suite, originally developed for drift chambers, and makes use of the MAGBOLTZ code to assess the drift parameters of electrons within the filling gas, and the SRIM code to evaluate the stopping range of fission products. The effect of the gamma flux is also estimated. Computations made with several fission chambers exemplify the possibilities of the route. A good qualitative agreement is obtained when comparing the results with the experimental data available to date. In a near future, a comprehensive experimental programme will be undertaken to qualify the route using the known neutron sources, mock-up reactors and wide choice of fission chambers, with a stress on the predictiveness of the Campbelling mode. Depending on the results, a refinement of the modelling and an effort on the accuracy of input data are also to be considered. CHESTER will then make it possible to predict the overall sensitivity of a chamber, and to optimize the design for a given application. Another benefit will be to increase the

  4. Estimation, comparison, and evaluation of advanced fission power reactor generation costs

    International Nuclear Information System (INIS)

    Waddell, J.D.

    1977-01-01

    The study compares the high-temperature gas-cooled reactor (HTGR), the gas-cooled fast reactor (GCFR), the molten-salt breeder reactor (MSBR), the light water breeder reactor (LWBR), and the heavy water reactor (HWR) with proposed light water reactors (LWR) and liquid-metal fast breeder reactors (LMFBR). The relative electrical generation costs, including the effects of the introduction of advanced reactor fuel cycles into the U.S. nuclear power economy, were projected through the year 2030. The study utilized the NEEDS computer code which is a simulation of the U.S. nuclear power economy. The future potential electrical generation costs and cumulative consumption of uranium ore were developed using characterizations of the advanced systems. The reactor-fuel cycle characterizations were developed from literature reviews and personal discussions with the proponents of the various systems. The study developed a ranking of the concepts based on generation costs and uranium consumption

  5. Uranium content of coal ashes from Southern Brazil coal fueled power stations, by the fission track registration technique

    International Nuclear Information System (INIS)

    Morales, R.K.

    1981-01-01

    The feasibility of the application of the fission track registration technique for the determination of uranium in coal ashes was shown. The wet method was employed using as detector the Makrofol KG=10 μm, manufactured by Bayer. The coal ashes were originated from coal-fueled power stations localized in Southern Brazil. The results obtained ranged from 10 to 27 mg U/kg. Since the total error variation was from 18,4% to 23,8%, the method used was considered excellent. The determination of the uranium content in coal ashes is of considerable interest in environmental control in power stations, in their vicinity and wherever these ashes are used or stored. The technique used is the work proved to be very appropriate for the purpose aimed at. (Author) [pt

  6. Comparative evaluation of solar, fission, fusion, and fossil energy resources. Part 1: Solar energy

    Science.gov (United States)

    Williams, J. R.

    1974-01-01

    The utilization of solar energy to meet the energy needs of the U.S. is discussed. Topics discussed include: availability of solar energy, solar energy collectors, heating for houses and buildings, solar water heater, electric power generation, and ocean thermal power.

  7. Overview on international experimental programmes on power ramping and fission gas release

    International Nuclear Information System (INIS)

    Knaab, H.; Lang, P.M.; Mogard, H.

    1983-01-01

    During the last years a number of internationally sponsored experimental programmes were initiated to study the LWR fuel behaviour during ramping and fission gas release at higher burnup levels. Common interest and the limited availability of experimental facilities and appropriate test fuel rods have led to valuable cooperation of many organizations throughout the nuclear community. These programmes are performed by the experimental staff from research centers with their experimental facilities. Fuel vendors and several utilities contribute by supply and irradiation of test fuel rods. The aim of this paper is to provide a synopsis of the following programmes: Studsvik Projects: Interramp, Overramp, Superramp, Demoramp I and II; Petten, High Burnup PWR Ramp Test Programme; Mol, Tribulation Programme; BNWL, High Burnup Effects Programme; Risoe Fission Gas Project; Related tasks within the OECD Halden Reactor Project. The objectives of the programme, their work scope and main results will be summarized on the basis of presently available information. An outlook to future proposed programmes will be given. (author)

  8. Overview on international experimental programmes on power ramping and fission gas release

    International Nuclear Information System (INIS)

    Knaab, H.; Lang, P.M.

    1985-01-01

    During the last few years a number of internationally sponsored experimental programmes have been initiated to study LWR fuel behaviour during ramping and fission gas release at high burnup levels. Common interest and the limited availability of experimental facilities and appropriate test fuel rods have led to valuable cooperation between many organizations throughout the nuclear community. These programmes are carried out by experienced staff from research centres using the centres' experimental facilities. Fuel vendors and several utilities contribute by supplying and irradiating the test fuel rods. The aim of this paper is to provide a synopsis of the following programmes: (a) Studsvik Projects: Interramp, Demoramp I and II, Overramp, Superramp; (b) Petten, High Burnup PWR Ramp Test Programme; (c) Mol, Tribulation Programme; (d) BNWL, High Burnup Effects Programme; (e) Riso Fission Gas Project; and (f) related tasks within the OECD Halden Reactor Project. The objectives of the programmes, their scope and the main results will be summarized. An overview of proposed future programmes will be given. (author)

  9. A Comparison of Fission Power System Options for Lunar and Mars Surface Applications

    International Nuclear Information System (INIS)

    Mason, Lee S.

    2006-01-01

    This paper presents a comparison of reactor and power conversion design options for 50 kWe class lunar and Mars surface power applications with scaling from 25 to 200 kWe. Design concepts and integration approaches are provided for three reactor-converter combinations: gas-cooled Brayton, liquid-metal Stirling, and liquid-metal thermoelectric. The study examines the mass and performance of low temperature, stainless steel based reactors and higher temperature refractory reactors. The preferred system implementation approach uses crew-assisted assembly and in-situ radiation shielding via installation of the reactor in an excavated hole. As an alternative, self-deployable system concepts that use earth-delivered, on-board radiation shielding are evaluated. The analyses indicate that among the 50 kWe stainless steel reactor options, the liquid-metal Stirling system provides the lowest mass at about 5300 kg followed by the gas-cooled Brayton at 5700 kg and the liquid-metal thermoelectric at 8400 kg. The use of a higher temperature, refractory reactor favors the gas-cooled Brayton option with a system mass of about 4200 kg as compared to the Stirling and thermoelectric options at 4700 kg and 5600 kg, respectively. The self-deployed concepts with on-board shielding result in a factor of two system mass increase as compared to the in-situ shielded concepts

  10. HPS: A space fission power system suitable for near-term, low-cost lunar and planetary bases

    International Nuclear Information System (INIS)

    Houts, M.G.; Poston, D.I.; Ranken, W.A.

    1996-01-01

    Near-term, low-cost space fission power systems can enhance the feasibility and utility of lunar and planetary bases. One such system, the Heatpipe Power System (HPS), is described in this paper. The HPS draws on 40 yr of United States and international experience to enable a system that can be developed in <5 yr at a cost of <$100M. Total HPS mass is <600 kg at 5 kWe and <2000 kg at 50 kWe, assuming that thermoelectric power conversion is used. More advanced power conversion systems could reduce system mass significantly. System mass for planetary surface systems also may be reduced (1) if indigenous material is used for radiation shielding and (2) because of the positive effect of the gravitational field on heatpipe operation. The HPS is virtually non-radioactive at launch and is passively subcritical during all credible launch accidents. Full-system electrically heated testing is possible, and a ground nuclear power test is not needed for flight qualification. Fuel burnup limits are not reached for several decades, thus giving the system long-life potential

  11. Health and safety. Preliminary comparative assessment of the satellite power system (SPS) and other energy alternatives

    International Nuclear Information System (INIS)

    Habegger, L.J.; Gasper, J.R.; Brown, C.D.

    1980-04-01

    Existing data on the health and safety risks of a satellite power system and four electrical generation systems are analyzed: a combined-cycle coal power system with a low-Btu gasifier and open-cycle gas turbine, a fission power system with fuel reprocessing, a central-station, terrestrial, solar-photovoltaic power system, and a first-generation design for a fusion power system. The systems are compared on the basis of expected deaths and person-days lost per year associated with 1000 MW of average electricity generation and the number of health and safety risks that are identified as potentially significant but unquantifiable. The appendices provide more detailed information on risks, uncertainties, additional research needed, and references for the identified impacts of each system

  12. The gamma spectrometry a powerful tool for irradiated fuel and fission products release studies

    International Nuclear Information System (INIS)

    Pontillon, Y.; Roure, C.; Lacroix, B.; Martella, T.; Ducros, G.; Ravel, S.; Gleizes, B.

    2003-01-01

    Over the last decades, due to the potentially severe consequences of a nuclear incident and/or accident for surrounding populations as well as the environment, international safety authorities launched R and D programs in support of general policy on exploitation of nuclear energy. This increasing interest enabled starting of many research programs in CEA and particularly in Nuclear Energy Directorate (DEN). Most of them are devoted to (i) the source term of fission products (including gas) and actinides released from PWR fuel samples in normal or accident conditions, (ii) burn-up determination, (iii) isotopic repartition... by quantitative gamma spectrometry. In this context, the Department of Fuel Studies (DEC), part of the DEN, has acquired considerable experience in this field of research. In order to attain the required capabilities, specific technical facilities set up in shielded hot cells at the CEA-Grenoble and CEA-Cadarache have been developed. In particular, the researchers of the Department have developed several gamma scanning benches and a set of two thermal treatment devices, including the so-called 'VERCORS facility'. These devices are associated to on line quantitative gamma spectrometry, in order to measure emitted gas and fission products (FPs). The greatest asset of such installations is to ensure a high analytical experiments rate, and as a consequence to make parametrical approach of planned studies easier. The first part of the present communication focuses, on the one hand, on the peculiar aspects of the gamma spectrometry applied on irradiated fuel, mad on the other hand, on the technical aspect of the different facilities (i.e. quantitative gamma spectrometry apparatus and corresponding 'home made' software). The last part is devoted to the results which can be obtained with such installation. In particular, it will be explained how experimental programs on FPs and gas release in normal and/or accidental conditions can be conducted

  13. Nuclear fission

    International Nuclear Information System (INIS)

    Kodama, T.

    1981-01-01

    The nuclear fission process is pedagogically reviewed from a macroscopic-microscopic point of view. The Droplet model is considered. The fission dynamics is discussed utilizing path integrals and semiclassical methods. (L.C.) [pt

  14. Investigation of applications for high-power, self-critical fissioning uranium plasma reactors. Final technical report

    International Nuclear Information System (INIS)

    Rodgers, R.J.; Latham, T.S.; Krascella, N.L.

    1976-09-01

    Analytical studies were conducted to investigate potentially attractive applications for gaseous nuclear cavity reactors fueled by uranium hexafluoride and its decomposition products at temperatures of 2000 to 6000 K and total pressures of a few hundred atmospheres. Approximate operating conditions and performance levels for a class of nuclear reactors in which fission energy removal is accomplished principally by radiant heat transfer from the high temperature gaseous nuclear fuel to surrounding absorbing media were determined. The results show the radiant energy deposited in the absorbing media may be efficiently utilized in energy conversion system applications which include (1) a primary energy source for high thrust, high specific impulse space propulsion, (2) an energy source for highly efficient generation of electricity, and (3) a source of high intensity photon flux for heating working fluid gases for hydrogen production or MHD power extraction. (Author)

  15. Intermediate energy nuclear fission

    International Nuclear Information System (INIS)

    Hylten, G.

    1982-01-01

    Nuclear fission has been investigated with the double-kinetic-energy method using silicon surface barrier detectors. Fragment energy correlation measurements have been made for U, Th and Bi with bremsstrahlung of 600 MeV maximum energy. Distributions of kinetic energy as a function of fragment mass are presented. The results are compared with earlier photofission data and in the case of bismuth, with calculations based on the liquid drop model. The binary fission process in U, Yb, Tb, Ce, La, Sb, Ag and Y induced by 600 MeV protons has been investigated yielding fission cross sections, fragment kinetic energies, angular correlations and mass distributions. Fission-spallation competition calculations are used to deduce values of macroscopic fission barrier heights and nuclear level density parameter values at deformations corresponding to the saddle point shapes. We find macroscopic fission barriers lower than those predicted by macroscopic theories. No indication is found of the Businaro Gallone limit expected to occur somewhere in the mass range A = 100 to A = 140. For Ce and La asymmetric mass distributions similar to those in the actinide region are found. A method is described for the analysis of angular correlations between complementary fission products. The description is mainly concerned with fission induced by medium-energy protons but is applicable also to other projectiles and energies. It is shown that the momentum and excitation energy distributions of cascade residuals leading to fission can be extracted. (Author)

  16. Comparative health and safety assessment of the satellite power system and other electrical generation alternatives

    International Nuclear Information System (INIS)

    1980-12-01

    The work reported here is an analysis of existing data on the health and safety risks of a satellite power system and six electrical generation systems: a combined-cycle coal power system with a low-Btu gasifier and open-cycle gas turbine; a light water fission power system without fuel reprocessing; a liquid-metal, fast-breeder fission reactor; a centralized and decentralized, terrestrial, solar-photovoltaic power system; and a first-generation design for a fusion power system. The systems are compared on the basis of expected deaths and person-days lost per year associated with 1000 MW of average electricity generation. Risks are estimated and uncertainties indicated for all phases of the energy production cycle, including fuel and raw material extraction and processing, direct and indirect component manufacture, on-site construction, and system operation and maintenance. Also discussed is the potential significance of related major health and safety issues that remain largely unquantifiable. The appendices provide more detailed information on risks, uncertainties, additional research needed, and references for the identified impacts of each system

  17. Low-cost space fission power systems utilizing US and former Soviet Union experience and technology

    International Nuclear Information System (INIS)

    Wetch, J.R.; Britt, E.J.; Koester, J.K.; Gunther, N.; Ponomarev-Stepnoi, N.N.; Nikolaev, Y.V.; Nikitin, V.

    1997-01-01

    This report summarizes the author close-quote s approach to space power total economics. In the past 40 years of U.S. government sponsored space nuclear power developments, total economics has received only token consideration. In the real world, nuclear power has had limited acceptance where it provided the enabling capability i.e. isotopes for low power, long life, deep space missions, or reactor power for underwater nuclear submarines. It was also accepted where it was perceived to be more economic. Examples are nuclear reactor powered aircraft carriers, escort vessels and central station power stations. In any case, real and perceived public and environmental safety must always be included into the economic equation. copyright 1997 American Institute of Physics

  18. Comparative evaluation of solar, fission, fusion, and fossil energy resources. Part 4: Energy from fossil fuels

    Science.gov (United States)

    Williams, J. R.

    1974-01-01

    The conversion of fossil-fired power plants now burning oil or gas to burn coal is discussed along with the relaxation of air quality standards and the development of coal gasification processes to insure a continued supply of gas from coal. The location of oil fields, refining areas, natural gas fields, and pipelines in the U.S. is shown. The technologies of modern fossil-fired boilers and gas turbines are defined along with the new technologies of fluid-bed boilers and MHD generators.

  19. A simple method to evaluate the fission gas release at fuel grain boundary including the grain growth both at constant and at transient power histories

    International Nuclear Information System (INIS)

    Paraschiv, M.; Paraschiv, A.

    1991-01-01

    A method to rewrite Fick's second law for a region with a moving boundary when the moving law in time of this boundary is known, has been proposed. This method was applied to Booth's sphere model for radioactive and stable fission product diffusion from the oxide fuel grain in order to take into account the grain growth. The solution of this new equation was presented in the mathematical formulation for power histories from ANS 5.4 model for the stable species. It is very simple to apply and very accurate. The results obtained with this solution for constant and transient temperatures show that the fission gas release (FGR) at grain boundary is strongly dependent on kinetics of grain growth. The utilization of two semiempirical grain growth laws, from published information, shows that the fuel microstructural properties need to be multicitly considered in the fission gas release for every manufacturer of fuel. (orig.)

  20. The nuclear fission process

    International Nuclear Information System (INIS)

    Wagemans, C.

    1991-01-01

    Fifty years after its discovery, the nuclear fission phenomenon is of recurring interest. When its fundamental physics aspects are considered, fission is viewed in a very positive way, which is reflected in the great interest generated by the meetings and large conferences organized for the 50th anniversary of its discovery. From a purely scientific and practical point of view, a new book devoted to the (low energy) nuclear fission phenomenon was highly desirable considering the tremendous amount of new results obtained since the publication of the book Nuclear Fission by Vandenbosch and Huizenga in 1973 (Academic Press). These new results could be obtained thanks to the growth of technology, which enabled the construction of powerful new neutron sources, particle and heavy ion accelerators, and very performant data-acquisition and computer systems. The re-invention of the ionization chamber, the development of large fission fragment spectrometers and sophisticated multiparameter devices, and the production of exotic isotopes also contributed significantly to an improved understanding of nuclear fission. This book is written at a level to introduce graduate students to the exciting subject of nuclear fission. The very complete list of references following each chapter also makes the book very useful for scientists, especially nuclear physicists. The book has 12 chapters covering the fission barrier and the various processes leading to fission as well as the characteristics of the various fission reaction products. In order to guarantee adequate treatment of the very specialized research fields covered, several distinguished scientists actively involved in some of these fields were invited to contribute their expertise as authors or co-authors of the different chapters

  1. Calculation of neutron interior source distribution within subcritical fission-chain reacting systems for a prescribed power density generation

    International Nuclear Information System (INIS)

    Moraes, Leonardo R.C.; Alves Filho, Hermes; Barros, Ricardo C.

    2017-01-01

    Accelerator Driven Systems (ADS) are sub-critical systems stabilized by stationary external sources of neutrons. A system is subcritical when the removal by absorption and leakage exceeds the production by fission and tends to shut down. On the other hand, any subcritical system can be stabilized by including time-independent external sources of neutrons. The goal of this work is to determine the intensity of uniform and isotropic sources of neutrons that must be added inside all fuel regions of a subcritical system so that it becomes stabilized, generating a prescribed distribution of electric power. A computer program has been developed in Java language to estimate the intensity of stationary sources of neutrons that must be included in the fuel regions to drive the subcritical system with a fixed power distribution prescribed by the user. The mathematical model used to achieve this goal was the energy multigroup, slab-geometry neutron transport equation in the discrete ordinates (S N ) formulation and the response matrix method was applied to solve the forward and the adjoint S N problems. Numerical results are given to verify the present. (author)

  2. Calculation of neutron interior source distribution within subcritical fission-chain reacting systems for a prescribed power density generation

    Energy Technology Data Exchange (ETDEWEB)

    Moraes, Leonardo R.C.; Alves Filho, Hermes; Barros, Ricardo C., E-mail: lrcmoraes@iprj.uerj.br, E-mail: halves@iprj.uerj.br, E-mail: ricardob@iprj.uerj.br [Universidade do Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil). Programa de Pós-Graduação em Modelagem Computacional

    2017-07-01

    Accelerator Driven Systems (ADS) are sub-critical systems stabilized by stationary external sources of neutrons. A system is subcritical when the removal by absorption and leakage exceeds the production by fission and tends to shut down. On the other hand, any subcritical system can be stabilized by including time-independent external sources of neutrons. The goal of this work is to determine the intensity of uniform and isotropic sources of neutrons that must be added inside all fuel regions of a subcritical system so that it becomes stabilized, generating a prescribed distribution of electric power. A computer program has been developed in Java language to estimate the intensity of stationary sources of neutrons that must be included in the fuel regions to drive the subcritical system with a fixed power distribution prescribed by the user. The mathematical model used to achieve this goal was the energy multigroup, slab-geometry neutron transport equation in the discrete ordinates (S{sub N}) formulation and the response matrix method was applied to solve the forward and the adjoint S{sub N} problems. Numerical results are given to verify the present. (author)

  3. Behavior of fission products released from severely damaged fuel during the PBF severe fuel damage tests

    International Nuclear Information System (INIS)

    Osetek, D.J.; Cronenberg, A.W.; Hagrman, D.L.; Broughton, J.M.; Rest, J.

    1984-01-01

    The results of fission product release behavior during the first two Power Burst Facility Severe Fuel Damage tests are presented. Measured fission product release is compared with calculated release using temperature dependent release rate correlations and FASTGRASS analysis. The test results indicate that release from fuel of the high volatility fission products (Xe, Kr, I, Cs, and Te) is strongly influenced by parameters other than fuel temperature; namely fuel/fission product morphology, fuel and cladding oxidation state, extent of fuel liquefaction, and quench induced fuel shattering. Fission product transport from the test fuel through the sample system was strongly influenced by chemical effects. Holdup of I and Cs was affected by fission product chemistry, and transport time while Te release was primarily influenced by the extent of zircaloy oxidation. Analysis demonstrates that such integral test data can be used to confirm physical, chemical, and mechanistic models of fission product behavior for severe accident conditions

  4. Comparative retention of fission fragment 147Pm in regenerated and fetal liver on induction of chromosome aberrations in these cells

    International Nuclear Information System (INIS)

    Zhu Shoupeng; Zheng Siying; Wang Liuyi; Yang Shujin

    1989-01-01

    The purpose of the present study is to ascertain comparative retention of fission fragment 147 Pm in regenerated and fetal liver on induction of chromosome aberrations in these cells. The results indicated that retention of 147 Pm in regenerated liver was about 700 times than in fetal liver. The cumulative absorption dose in regenerated liver was about 2.87 Gy, while in fetal liver-only 0.004 Gy. Under the same conditions, the incidence rate of chromosome aberrations in regenerated liver cells induced by 147 Pm was 50.2%, and in fetal liver cells-about 28.3%. It should be concluded that the radiosensitivity to 147 Pm was not uniform among the regenerated and fetal liver cells. The study suggested that fetal liver cells show to be more radiosensitive to 147 Pm than regenerated liver cells. Among the type of aberrations in both cells induced by 147 Pm, chromatid breakages were predominant, accompanied with a few chromosome breakages

  5. Comparative studies between nuclear power plants and hydroelectric power plants

    International Nuclear Information System (INIS)

    Menegassi, J.

    1984-01-01

    This paper shows the quantitative evolution of the power plants in the main countries of the world. The Brazilian situation is analysed, with emphasys in the technical and economical aspects related to power production by hidroelectric or nuclear power plants. The conclusion is that the electricity produced by hidro power plants becomes not economics when is intended to be produced at large distances from the demand centers. (Author) [pt

  6. Computer program FPIP-REV calculates fission product inventory for U-235 fission

    Science.gov (United States)

    Brown, W. S.; Call, D. W.

    1967-01-01

    Computer program calculates fission product inventories and source strengths associated with the operation of U-235 fueled nuclear power reactor. It utilizes a fission-product nuclide library of 254 nuclides, and calculates the time dependent behavior of the fission product nuclides formed by fissioning of U-235.

  7. Next generation laser optics for a hybrid fusion-fission power plant

    Energy Technology Data Exchange (ETDEWEB)

    Stolz, C J; Latkowski, J T; Schaffers, K I

    2009-09-10

    The successful completion of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL), followed by a campaign to achieve ignition, creates the proper conditions to begin exploring what development work remains to construct a power plant based on Inertial Confinement Fusion (ICF) technology. Fundamentally, two distinct NIF laser properties must be overcome. The repetition rate must increase from a shot every four hours to several shots per second. Additionally, the efficiency of converting electricity to laser light must increase by 20x to roughly 10 percent. Solid state diode pumped lasers, commercially available for table top applications, have adequate repetition rates and power conversion efficiencies, however, they operate at a tiny fraction of the required energy for an ICF power plant so would need to be scaled in energy and aperture. This paper describes the optics and coatings that would be needed to support this type of laser architecture.

  8. Fission products in the spent nuclear fuel from czech nuclear power plants

    International Nuclear Information System (INIS)

    Lelek, V.; Mikisek, M.; Marek, T.

    1999-01-01

    The nuclear power is expected to become a supply able to cover a significant part of the world energetic demand in future. But its big disadvantage, the risk of the spent nuclear fuel, has to be solved. The aim of this paper is to make simple estimates of the upper limits of amounts of the most dangerous spent fuel components and their compounds produced in Czech Republic until 2040. Our estimates are independent on particular type reactor (only on its power) and so they can be carried out for any nuclear fuel cycle. (Authors)

  9. Detection of fission fragments by secondary emission; Detection des fragments de fission par emission secondaire

    Energy Technology Data Exchange (ETDEWEB)

    Audias, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    This fission fragment detecting apparatus is based on the principle that fragments traversing a thin foil will cause emission of secondary electrons. These electrons are then accelerated (10 kV) and directly detected by means of a plastic scintillator and associated photomultiplier. Some of the advantages of such a detector are, its rapidity, its discriminating power between alpha particles and fission fragments, its small energy loss in detecting the fragments and the relatively great amount of fissionable material which it can contain. This paper is subdivided as follows: a) theoretical considerations b) constructional details of apparatus and some experimental details and c) a study of the secondary emission effect itself. (author) [French] Le detecteur de fragments de fission que nous avons realise est base sur le principe de l'emission secondaire produite par les fragments de fission traversant une feuille mince: les electrons secondaires emis sont acceleres a des tensions telles (de l'ordre de 10 kV), qu'ils soient directement detectables par un scintillateur plastique associe a un photomultiplicateur. L'interet d'un tel detecteur reside: dans sa rapidite, sa tres bonne discrimination alpha, fission, la possibilite de detecter les fragments de fission avec une perte d'energie pouvant rester relativement faible, et la possibilite d'introduire des quantites de matiere fissile plus importantes que dans les autres types de detecteurs. Ce travail comporte: -) un apercu bibliographique de la theorie du phenomene, -) realisation et mise au point du detecteur avec etude experimentale de quelques parametres intervenant dans l'emission secondaire, -) etude de l'emission secondaire (sur la face d'emergence des fragments de fission) en fonction de l'energie du fragment et en fonction de l'epaisseur de matiere traversee avant emission secondaire, et -) une etude comparative de l'emission secondaire sur la face d'incidence et sur la face d'emergence des fragments de

  10. High-safety and economical small molten-salt fission power stations and their developmental program

    International Nuclear Information System (INIS)

    Furukawa, K.; Mitachi, K.; Minami, K.; Kato, Y.

    1988-01-01

    The nuclear energy industry is not settled yet as one of the sound economical industries. Its establishment should obviously depend on the solution of the following problems: ''natural'' safety (depending on inherent natures), nuclear proliferation resistance - nearly non-production and effective incineration of Pu, Am and Om, universal resource, flexible power-size and excellent economy - wide applicability including Developing Countries. Therefore, some essentially new principles have to introduce in the nuclear energy system design. These are thorium utilization, fluid-fuel concepts, especially molten-fluoride technology, and separation of fissile-breeding and power-generation. This philosophy is named Thorium Molten-Salt Nuclear Energy Synergetics [THOMSNES]. Its practical development program is presented

  11. Assessments of sheath strain and fission gas release data from 20 years of power reactor fuel irradiations

    International Nuclear Information System (INIS)

    Purdy, P.L.; Manzer, A.M.; Hu, R.H.; Gibb, R.A.; Kohn, E.

    1997-01-01

    Over the past 20 years, many fuel elements or bundles discharged from Canadian CANDU power reactors have been examined in the AECL hot cells. The post-irradiation examination (PIE) database covers a wide range of operating conditions, from which fuel performance characteristics can be assessed. In the present analysis, a PIE database was compiled representing elements from a total of 129 fuel bundles, of which 26% (34 bundles) were confirmed to have one or more defective elements. This comprehensive database was assessed in terms of measured sheath strain and fission gas release (FGR) for intact elements, in an attempt to identify any changes in these parameters over the history of CANDU reactor operation. Results from this assessment indicate that, for the data that are typical of normal CANDU operating conditions, tensile sheath strain and FGR have remained within 0.5% and 8%, respectively. Those data beyond these ranges are from fuel operated under abnormal conditions, not representative of normal operation, and thus do not indicate a trend toward unexpected fuel behaviour. The distributions of the PIE measurements indicate that maximum expected sheath strains and FGR for normally operated fuel are 0.7% and 13%, respectively. (author)

  12. Comparative studies of the relation costs/benefits of the production methods of 99Mo: fission of 235U and neutron capture reaction on 98Mo

    International Nuclear Information System (INIS)

    Takahashi, Sergio Yukio

    2004-01-01

    This work analyses the benefits and costs that are the results of the production of Technetium generators, using 99 Mo produced by two different ways. For this analysis, the production process of 99 Mo, nowadays imported, obtained through the fission of uranium. The second process is the gel generator that is totally national, developed by researcher at IPEN. The self-sustained costs were evaluated for both production processes. The conclusion was that although positive and negative aspects appear in both processes, they must remain: Fission Mo will supply the generators with activities higher than 1.85x10 10 Bq and the gel generator will supply activities up to 1.85x10 10 Bq. This limitation can be overcome if the power of the Reactor is upgraded and if the irradiation time covers the 3 shifts. (author)

  13. Conceptual design of the blanket and power conversion system for a mirror hybrid fusion-fission reactor. 12-month progress report, July 1, 1975--June 30, 1976

    International Nuclear Information System (INIS)

    Schultz, K.R.; Baxi, C.B.; Rao, R.

    1976-01-01

    This report presents the conceptual design and preliminary feasibility assessment for the hybrid blanket and power conversion system of the Mirror Hybrid Fusion-Fission Reactor. Existing gas-cooled fission reactor technology is directly applicable to the Mirror Hybrid Reactor. There are a number of aspects of the present conceptual design that require further design and analysis effort. The blanket and power conversion system operating parameters have not been optimized. The method of supporting the blanket modules and the interface between these modules and the primary loop helium ducting will require further design work. The means of support and containment of the primary loop components must be studied. Nevertheless, in general, the conceptual design appears quite feasible

  14. Correlated prompt fission data in transport simulations

    Science.gov (United States)

    Talou, P.; Vogt, R.; Randrup, J.; Rising, M. E.; Pozzi, S. A.; Verbeke, J.; Andrews, M. T.; Clarke, S. D.; Jaffke, P.; Jandel, M.; Kawano, T.; Marcath, M. J.; Meierbachtol, K.; Nakae, L.; Rusev, G.; Sood, A.; Stetcu, I.; Walker, C.

    2018-01-01

    Detailed information on the fission process can be inferred from the observation, modeling and theoretical understanding of prompt fission neutron and γ-ray observables. Beyond simple average quantities, the study of distributions and correlations in prompt data, e.g., multiplicity-dependent neutron and γ-ray spectra, angular distributions of the emitted particles, n - n, n - γ, and γ - γ correlations, can place stringent constraints on fission models and parameters that would otherwise be free to be tuned separately to represent individual fission observables. The FREYA and CGMF codes have been developed to follow the sequential emissions of prompt neutrons and γ rays from the initial excited fission fragments produced right after scission. Both codes implement Monte Carlo techniques to sample initial fission fragment configurations in mass, charge and kinetic energy and sample probabilities of neutron and γ emission at each stage of the decay. This approach naturally leads to using simple but powerful statistical techniques to infer distributions and correlations among many observables and model parameters. The comparison of model calculations with experimental data provides a rich arena for testing various nuclear physics models such as those related to the nuclear structure and level densities of neutron-rich nuclei, the γ-ray strength functions of dipole and quadrupole transitions, the mechanism for dividing the excitation energy between the two nascent fragments near scission, and the mechanisms behind the production of angular momentum in the fragments, etc. Beyond the obvious interest from a fundamental physics point of view, such studies are also important for addressing data needs in various nuclear applications. The inclusion of the FREYA and CGMF codes into the MCNP6.2 and MCNPX - PoliMi transport codes, for instance, provides a new and powerful tool to simulate correlated fission events in neutron transport calculations important in

  15. Correlated prompt fission data in transport simulations

    Energy Technology Data Exchange (ETDEWEB)

    Talou, P.; Jaffke, P.; Kawano, T.; Stetcu, I. [Los Alamos National Laboratory, Nuclear Physics Group, Theoretical Division, Los Alamos, NM (United States); Vogt, R. [Lawrence Livermore National Laboratory, Nuclear and Chemical Sciences Division, Livermore, CA (United States); University of California, Physics Department, Davis, CA (United States); Randrup, J. [Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Rising, M.E.; Andrews, M.T.; Sood, A. [Los Alamos National Laboratory, Monte Carlo Methods, Codes, and Applications Group, Los Alamos, NM (United States); Pozzi, S.A.; Clarke, S.D.; Marcath, M.J. [University of Michigan, Department of Nuclear Engineering and Radiological Sciences, Ann Arbor, MI (United States); Verbeke, J.; Nakae, L. [Lawrence Livermore National Laboratory, Nuclear and Chemical Sciences Division, Livermore, CA (United States); Jandel, M. [Los Alamos National Laboratory, Nuclear and Radiochemistry Group, Los Alamos, NM (United States); University of Massachusetts, Department of Physics and Applied Physics, Lowell, MA (United States); Meierbachtol, K. [Los Alamos National Laboratory, Nuclear Engineering and Nonproliferation, Los Alamos, NM (United States); Rusev, G.; Walker, C. [Los Alamos National Laboratory, Nuclear and Radiochemistry Group, Los Alamos, NM (United States)

    2018-01-15

    Detailed information on the fission process can be inferred from the observation, modeling and theoretical understanding of prompt fission neutron and γ-ray observables. Beyond simple average quantities, the study of distributions and correlations in prompt data, e.g., multiplicity-dependent neutron and γ-ray spectra, angular distributions of the emitted particles, n-n, n-γ, and γ-γ correlations, can place stringent constraints on fission models and parameters that would otherwise be free to be tuned separately to represent individual fission observables. The FREYA and CGMF codes have been developed to follow the sequential emissions of prompt neutrons and γ rays from the initial excited fission fragments produced right after scission. Both codes implement Monte Carlo techniques to sample initial fission fragment configurations in mass, charge and kinetic energy and sample probabilities of neutron and γ emission at each stage of the decay. This approach naturally leads to using simple but powerful statistical techniques to infer distributions and correlations among many observables and model parameters. The comparison of model calculations with experimental data provides a rich arena for testing various nuclear physics models such as those related to the nuclear structure and level densities of neutron-rich nuclei, the γ-ray strength functions of dipole and quadrupole transitions, the mechanism for dividing the excitation energy between the two nascent fragments near scission, and the mechanisms behind the production of angular momentum in the fragments, etc. Beyond the obvious interest from a fundamental physics point of view, such studies are also important for addressing data needs in various nuclear applications. The inclusion of the FREYA and CGMF codes into the MCNP6.2 and MCNPX-PoliMi transport codes, for instance, provides a new and powerful tool to simulate correlated fission events in neutron transport calculations important in nonproliferation

  16. On the selfacting safe limitation of fission power and fuel temperature in innovative nuclear reactors

    International Nuclear Information System (INIS)

    Scherer, W.; Brockmann, H.; Drecker, S.; Gerwin, H.; Haas, K.A.; Kugeler, K.; Ohlig, U.; Ruetten, H.J.; Teuchert, E.; Werner, H.; Wolf, L.

    1994-08-01

    Nuclear energy probably will not contribute significantly to the future worldwide energy supply until it can be made catastrophe-free. Therefore it has to be shown, that the consequences of even largest accidents will have no major impact to the environment of a power plant. In this paper one of the basic conditions for such a nuclear technology is discussed. Using mainly the modular pebble-bed high-temperature reactor as an example, the design principles, analytical methods and the level of knowledge as given today in controlling reactivity accidents by inherent safety features of innovative nuclear reactors are described. Complementary possibilities are shown to reach this goal with systems of different types of construction. Questions open today and resulting requirements for future activities are discussed. Today's knowledge credibly supports the possibility of a catastrophe-free nuclear technology with respect to reactivity events. (orig.)

  17. Fusion-fission dynamics

    International Nuclear Information System (INIS)

    Blocki, J.; Planeta, R.; Brzychczyk, J.; Grotowski, K.

    1992-01-01

    Classical dynamical calculations of the heavy ion induced fission processes have been performed for the reactions 40 Ar+ 141 Pr, 20 Ne+ 165 Ho and 12 C+ 175 Lu leading to the iridium like nucleus. As a result prescission lifetimes were obtained and compared with the experimental values. The comparison between the calculated and experimental lifetimes indicates that the one-body dissipation picture is much more relevant in describing the fusion-fission dynamics than the two-body one. (orig.)

  18. Theory of nuclear fission: a review

    International Nuclear Information System (INIS)

    Mosel, U.

    1976-01-01

    General properties of nuclear fission are reviewed and related to our present knowledge of fission theory. For this purpose the basic reasons for the shape of the fission barriers are discussed and their consequences compared with experimental results on barrier shapes and structures. Special emphasis is put on the asymmetry of the fission barriers and mass-distributions and its relation to the shells of the nascent fragment shells. Finally the problem of calculating fission cross sections is discussed

  19. Methodology for the comparative assessment of the Satellite Power System (SPS) and alternative technologies

    Energy Technology Data Exchange (ETDEWEB)

    Wolsko, T.; Buehring, W.; Cirillo, R.; Gasper, J.; Habegger, L.; Hub, K.; Newsom, D.; Samsa, M.; Stenehjem, E.; Whitfield, R.

    1980-01-01

    A description of the initial methodology for the Comparative Assessment of the Satellite Power System Concept Development and Evaluation Program of NASA and DOE is presented. Included are study objectives, issue identification, units of measurement, methods, and data bases. The energy systems concerned are the satellite power system, several coal technologies, geothermal energy, fission, fusion, terrestrial solar systems, and ocean thermal energy conversion. Guidelines are suggested for the characterization of these systems, side-by-side analysis, alternative futures analysis, and integration and aggregation of data. The bulk of this report is a description of the methods for assessing the technical, economic, environmental, societal, and institutional issues surrounding the development of the selected energy technologies.

  20. Fission yield measurements at IGISOL

    Science.gov (United States)

    Lantz, M.; Al-Adili, A.; Gorelov, D.; Jokinen, A.; Kolhinen, V. S.; Mattera, A.; Moore, I.; Penttilä, H.; Pomp, S.; Prokofiev, A. V.; Rakopoulos, V.; Rinta-Antila, S.; Simutkin, V.; Solders, A.

    2016-06-01

    The fission product yields are an important characteristic of the fission process. In fundamental physics, knowledge of the yield distributions is needed to better understand the fission process. For nuclear energy applications good knowledge of neutroninduced fission-product yields is important for the safe and efficient operation of nuclear power plants. With the Ion Guide Isotope Separator On-Line (IGISOL) technique, products of nuclear reactions are stopped in a buffer gas and then extracted and separated by mass. Thanks to the high resolving power of the JYFLTRAP Penning trap, at University of Jyväskylä, fission products can be isobarically separated, making it possible to measure relative independent fission yields. In some cases it is even possible to resolve isomeric states from the ground state, permitting measurements of isomeric yield ratios. So far the reactions U(p,f) and Th(p,f) have been studied using the IGISOL-JYFLTRAP facility. Recently, a neutron converter target has been developed utilizing the Be(p,xn) reaction. We here present the IGISOL-technique for fission yield measurements and some of the results from the measurements on proton induced fission. We also present the development of the neutron converter target, the characterization of the neutron field and the first tests with neutron-induced fission.

  1. Fission yield measurements at IGISOL

    Directory of Open Access Journals (Sweden)

    Lantz M.

    2016-01-01

    Full Text Available The fission product yields are an important characteristic of the fission process. In fundamental physics, knowledge of the yield distributions is needed to better understand the fission process. For nuclear energy applications good knowledge of neutroninduced fission-product yields is important for the safe and efficient operation of nuclear power plants. With the Ion Guide Isotope Separator On-Line (IGISOL technique, products of nuclear reactions are stopped in a buffer gas and then extracted and separated by mass. Thanks to the high resolving power of the JYFLTRAP Penning trap, at University of Jyväskylä, fission products can be isobarically separated, making it possible to measure relative independent fission yields. In some cases it is even possible to resolve isomeric states from the ground state, permitting measurements of isomeric yield ratios. So far the reactions U(p,f and Th(p,f have been studied using the IGISOL-JYFLTRAP facility. Recently, a neutron converter target has been developed utilizing the Be(p,xn reaction. We here present the IGISOL-technique for fission yield measurements and some of the results from the measurements on proton induced fission. We also present the development of the neutron converter target, the characterization of the neutron field and the first tests with neutron-induced fission.

  2. Power sources compared : The ultimate truth?

    NARCIS (Netherlands)

    Flipsen, S.F.J.

    2006-01-01

    Especially, during the last decade the demand for portable power is steadily rising due to the increasing wireless products integrated in our day-to-day lives (cellular phone, personal digital assistant (PDA) and of course the remote control for your television set or VCR). These portable consumer

  3. Potentials of fissioning plasmas

    International Nuclear Information System (INIS)

    Karlheinz, Thom.

    1979-01-01

    Successful experiments with the nuclear pumping of lasers have demonstrated that in gaseous medium the kinetic energy of fission fragments can be converted directly into non-equilibrium optical radiation. This confirms the concept that the fissioning medium in a gas-phase nuclear reactor shows an internal structure such as a plasma in nearly thermal equilibrium varying up to a state of extreme-non-equilibrium. The accompanying variations of temperatures, pressure and radiative spectrum suggest wide ranges of applications. For example, in the gas-phase fission reactor concept enriched uranium hexafluoride or an uranium plasma replaces conventional fuel elements and permits operation above the melting point of solid materials. This potential has been motivation for the US National Aeronautics and Space Administration (NASA) to conduct relevant research for high specific impulse propulsion in space. The need to separate the high temperature gaseous fuel from the surfaces of a containing vessel and to protect them against thermal radiation has led to the concept of an externally moderated reactor in which the fissioning gaseous material is suspended by fluid dynamic means and the flow of opaque buffer gas removes the power. The gaseous nuclear fuel can slowly be circulated through the reactor for continuous on-site reprocessing including the annihilation of transuranium actinides at fission when being fed back into the reactor. An equilibrium of the generation and destruction of such actinides at fission when being fed back into the reactor. An equilibrium of the generation and destruction of such actinides can thus be achieved. These characteristics and the unique radiative properties led to the expectation that the gas-phase fission reactor could feature improved safety, safeguarding and economy, in addition to new technologies such as processing, photochemistry and the transmission of power over large distances in space

  4. Mathematical model for the preliminary analysis of dual-mode space nuclear fission solid core power and propulsion systems, NUROC3A. AMS report No. 1239a

    Energy Technology Data Exchange (ETDEWEB)

    Grey, J.; Chow, S.

    1976-06-30

    The three-volume report describes a dual-mode nuclear space power and propulsion system concept that employs an advanced solid-core nuclear fission reactor coupled via heat pipes to one of several electric power conversion systems. Such a concept could be particularly useful for missions which require both relatively high acceleration (e.g., for planetocentric maneuvers) and high performance at low acceleration (e.g., on heliocentric trajectories or for trajectory shaping). The first volume develops the mathematical model of the system.

  5. Laser driven fusion fission hybrids

    International Nuclear Information System (INIS)

    Hansen, L.F.; Maniscalco, J.A.

    1977-11-01

    The role of the fusion-fission hybrid reactor (FFHR) as a fissile fuel and/or power producer is discussed. As long range options to supply the world energy needs, hybrid-fueled thermal-burner reactors are compared to liquid metal fast breeder reactors (LMFBR). A discussion of different fuel cycles (thorium, depleted uranium, and spent fuel) is presented in order to compare the energy multiplication, the production of fissile fuel, the laser efficiency and pellet gain requirements of the hybrid reactor. Lawrence Livermore Laboratory (LLL) has collaborated with Bechtel Corporation and with Westinghouse in two engineering design studies of laser fusion driven hybrid power plants. The hybrid designs which have resulted from these two studies are briefly described and analyzed by considering operational parameters, such as energy multiplication, power density, burn-up and plutonium production as a function time

  6. Comparing nuclear power with other energy sources

    International Nuclear Information System (INIS)

    Rey, Francisco C.

    2001-01-01

    The economics of electric generation of nuclear, hydro, oil and gas origin are compared. A similar comparison is also made from the health and environment standpoint for the fossil, nuclear, solar and wind generation. A risk assessment for energies of different origin is outlined and the significance of the greenhouse effect is emphasised. A comprehensive economic and environmental evaluation is recommended for the energy planning

  7. A comparative study of fission gas behaviour in UO2 and MOX fuels using the meteor fuel performance code

    International Nuclear Information System (INIS)

    Struzik, C.; Garcia, Ph.; Noirot, L.

    2002-01-01

    The paper reviews some of the fission-gas-related differences observed between MOX MIMAS AUC fuels and homogeneous UO 2 fuels. Under steady-state conditions, the apparently higher fractional release in MOX fuels is interpreted with the METEOR fuel performance code as a consequence of their lower thermal conductivity and the higher linear heat rates to which MOX fuel rods are subjected. Although more fundamental diffusion properties are needed, the apparently greater swelling of MOX fuel rods at higher linear heat rates can be ascribed to enhanced diffusion properties. (authors)

  8. Non-electrical uses of thermal energy generated in the production of fissile fuel in fusion--fission reactors: a comparative economic parametric analysis for a hybrid with or without synthetic fuel production

    International Nuclear Information System (INIS)

    Tai, A.S.; Krakowski, R.A.

    1979-01-01

    A parametric analysis has been carried out for testing the sensitivity of the synfuel production cost in relation to crucial economic and technologic quantities (investment costs of hybrid and synfuel plant, energy multiplication of the fission blanket, recirculating power fraction of the fusion driver, etc.). In addition, a minimum synfuel selling price has been evaluated, from which the fission--fusion--synfuel complex brings about a higher economic benefit than does the fusion--fission hybrid entirely devoted to fissile-fuel and electricity generation. Assuming an electricity cost of 2.7 cents/kWh, an annual investment cost per power unit of 4.2 to 6 $/GJ (132 to 189 k$/MWty) for the fission--fusion complex and 1.5 to 3 $/GJ (47 to 95 k$/MWty) for the synfuel plant, the synfuel production net cost (i.e., revenue = cost) varies between 6.5 and 8.6 $/GJ. These costs can compete with those obtained by other processes (natural gas reforming, resid partial oxidation, coal gasification, nuclear fission, solar electrolysis, etc.). This study points out a potential use of the fusion--fission hybrid other than fissile-fuel and electricity generation

  9. Attachment behavior of fission products to solution aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Takamiya, Koichi; Tanaka, Toru; Nitta, Shinnosuke; Itosu, Satoshi; Sekimoto, Shun; Oki, Yuichi; Ohtsuki, Tsutomu [Research Reactor Institute, Kyoto University, Osaka (Japan)

    2016-12-15

    Various characteristics such as size distribution, chemical component and radioactivity have been analyzed for radioactive aerosols released from Fukushima Daiichi Nuclear Power Plant. Measured results for radioactive aerosols suggest that the potential transport medium for radioactive cesium was non-sea-salt sulfate. This result indicates that cesium isotopes would preferentially attach with sulfate compounds. In the present work the attachment behavior of fission products to aqueous solution aerosols of sodium salts has been studied using a generation system of solution aerosols and spontaneous fission source of {sup 248}Cm. Attachment ratios of fission products to the solution aerosols were compared among the aerosols generated by different solutions of sodium salt. A significant difference according as a solute of solution aerosols was found in the attachment behavior. The present results suggest the existence of chemical effects in the attachment behavior of fission products to solution aerosols.

  10. Implementation of a Sage-Based Stirling Model Into a System-Level Numerical Model of the Fission Power System Technology Demonstration Unit

    Science.gov (United States)

    Briggs, Maxwell H.

    2011-01-01

    The Fission Power System (FPS) project is developing a Technology Demonstration Unit (TDU) to verify the performance and functionality of a subscale version of the FPS reference concept in a relevant environment, and to verify component and system models. As hardware is developed for the TDU, component and system models must be refined to include the details of specific component designs. This paper describes the development of a Sage-based pseudo-steady-state Stirling convertor model and its implementation into a system-level model of the TDU.

  11. Review of some problems encountered with In-Core Fission chambers and Self-Powered Neutron Detectors in PWR's. Tests - Present use - Outlook on the near future

    International Nuclear Information System (INIS)

    Duchene, Jean; Verdant, Robert.

    1979-01-01

    The working conditions of in-core detectors are investigated as well as some reliability problems which depend on nuclear environment (such as decrease of sensibility, loss of insulation...). Then we review the long-term irradiation tests in experimental reactor that have been carried out by the CEA these last years, with fission chambers (FC) and Self-Powered Detectors (SPD). The travelling probe system with moveable FC used in the 900 MWe PWR is briefly described. Finally an outlook on future possibilities is given; for instance the use of fixed SPD and a moveable FC in the same thimble, allowing recalibration of the fixed detectors [fr

  12. Ternary fission

    Indian Academy of Sciences (India)

    the energy minimization of all possible ternary breakups of a heavy radioactive nucleus. Further, within the TCM we have analysed the competition between different geometries as well as different positioning of the fragments. Also, an attempt was made to calculate the mass distribution of ternary fission process within the ...

  13. Low energy nuclear fission

    International Nuclear Information System (INIS)

    Nifenecker, H.

    1982-02-01

    In these lectures we present the liquid drop model of fission and compare some of its prediction with experiment. The liquid drop analogy allows to define in a rather simple and intuitive way a number of useful concepts and possible observables. We then discuss, using the example of the oscillator model, the generality of shell effects. We show how a synthesis of the liquid drop model and of the shell model can be made using the Strutinsky shell averaging procedure. Some experimental data related to the existence of shape isomers are presented and discussed. We conclude by discussing some aspects, both experimental and theoretical, of fission dynamics

  14. Low energy nuclear fission

    International Nuclear Information System (INIS)

    Nifenecker, H.

    1980-08-01

    In these lectures the liquid drop model of fission is presented and some of its predictions compared with experiment. The liquid drop analogy allows to define in a rather simple and intuitive way a number of useful concepts and possible observables. It is shown how a synthesis of the liquid drop model and of the shell model can be made using the Strutinsky shell averaging procedure. Some experimental data related to the existence of shape isomers are presented and discussed. We conclude by discussing some aspects, both experimental and theoretical, of fission dynamics

  15. Computer code and users' guide for the preliminary analysis of dual-mode space nuclear fission solid core power and propulsion systems, NUROC3A. AMS report No. 1239b

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, R.A.; Smith, W.W.

    1976-06-30

    The three-volume report describes a dual-mode nuclear space power and propulsion system concept that employs an advanced solid-core nuclear fission reactor coupled via heat pipes to one of several electric power conversion systems. The second volume describes the computer code and users' guide for the preliminary analysis of the system.

  16. Comparing Different Fault Identification Algorithms in Distributed Power System

    Science.gov (United States)

    Alkaabi, Salim

    A power system is a huge complex system that delivers the electrical power from the generation units to the consumers. As the demand for electrical power increases, distributed power generation was introduced to the power system. Faults may occur in the power system at any time in different locations. These faults cause a huge damage to the system as they might lead to full failure of the power system. Using distributed generation in the power system made it even harder to identify the location of the faults in the system. The main objective of this work is to test the different fault location identification algorithms while tested on a power system with the different amount of power injected using distributed generators. As faults may lead the system to full failure, this is an important area for research. In this thesis different fault location identification algorithms have been tested and compared while the different amount of power is injected from distributed generators. The algorithms were tested on IEEE 34 node test feeder using MATLAB and the results were compared to find when these algorithms might fail and the reliability of these methods.

  17. Fission meter

    Science.gov (United States)

    Rowland, Mark S [Alamo, CA; Snyderman, Neal J [Berkeley, CA

    2012-04-10

    A neutron detector system for discriminating fissile material from non-fissile material wherein a digital data acquisition unit collects data at high rate, and in real-time processes large volumes of data directly into information that a first responder can use to discriminate materials. The system comprises counting neutrons from the unknown source and detecting excess grouped neutrons to identify fission in the unknown source.

  18. International handling of fissionable material

    International Nuclear Information System (INIS)

    1975-01-01

    The opinion of the ministry for foreign affairs on international handling of fissionable materials is given. As an introduction a survey is given of the possibilities to produce nuclear weapons from materials used in or produced by power reactors. Principles for international control of fissionable materials are given. International agreements against proliferation of nuclear weapons are surveyed and methods to improve them are proposed. (K.K.)

  19. On fission product retention in the core of the low powered high temperature reactor under accident conditions

    International Nuclear Information System (INIS)

    Bastek, H.

    1984-01-01

    In the core of the high temperature reactor the fuel element and the coated particles contained herein provide the safest enclosure for fission products. The complex process of fission product transport out of the particle kernel, through the particle coating and within the fuel element graphite is described in a simplified form by the Fick's diffusion. The effective diffusion coefficient is used for calculation. Starting from the existing ideas of fission product transport five burn-up and temperature-dependent diffusion coefficients for Cesium in (Th,U)O 2 -kernels are derived in this study. The results have been gained from several fuel element radiation experiments in recent years, which showed extreme variation in regard to burn-up, temperature cycle, neutron flux and operation time. Cs-137 release measurements from single particle kernels were present from all the experiments. Furthermore, annealing tests of AVR-fuel elements were analyzed. Heat-temperatur and heating-time, the fuel element burn-up in the AVR-reactor, as well as the measured Cs-137 inventory of the fuel elements before and after annealing, are included in the investigation as essential parameters. With the aid of the derived diffusion coeffizients and already present data sets the Cs-137 release of fuel elements into a small reactor core is investigated under unrestricted core heat-up. While the released Cs-137 is derived mainly from defective particles at accident temperatures up to 1600 0 C, the main part diffuses through the particle coating at higher accident temperatures. (orig./HP) [de

  20. Comparative Life-Cycle Cost Analysis Of Solar Photovoltaic Power ...

    African Journals Online (AJOL)

    Comparative Life-Cycle Cost Analysis Of Solar Photovoltaic Power System And Diesel Generator System For Remote Residential Application In Nigeria. ... like capital cost, and diesel fuel costs are varied. The results show the photovoltaic system to be more cost-effective at low-power ranges of electrical energy supply.

  1. Fission fragment angular momentum

    International Nuclear Information System (INIS)

    Frenne, D. De

    1991-01-01

    Most of the energy released in fission is converted into translational kinetic energy of the fragments. The remaining excitation energy will be distributed among neutrons and gammas. An important parameter characterizing the scission configuration is the primary angular momentum of the nascent fragments. Neutron emission is not expected to decrease the spin of the fragments by more than one unit of angular momentum and is as such of less importance in the determination of the initial fragment spins. Gamma emission is a suitable tool in studying initial fragment spins because the emission time, number, energy, and multipolarity of the gammas strongly depend on the value of the primary angular momentum. The main conclusions of experiments on gamma emission were that the initial angular momentum of the fragments is large compared to the ground state spin and oriented perpendicular to the fission axis. Most of the recent information concerning initial fragment spin distributions comes from the measurement of isomeric ratios for isomeric pairs produced in fission. Although in nearly every mass chain isomers are known, only a small number are suitable for initial fission fragment spin studies. Yield and half-life considerations strongly limit the number of candidates. This has the advantage that the behavior of a specific isomeric pair can be investigated for a number of fissioning systems at different excitation energies of the fragments and fissioning nuclei. Because most of the recent information on primary angular momenta comes from measurements of isomeric ratios, the global deexcitation process of the fragments and the calculation of the initial fragment spin distribution from measured isomeric ratios are discussed here. The most important results on primary angular momentum determinations are reviewed and some theoretical approaches are given. 45 refs., 7 figs., 2 tabs

  2. Finite element simulation of fission gas release and swelling in UO2 fuel pellets

    International Nuclear Information System (INIS)

    Denis, Alicia C.

    1999-01-01

    A fission gas release model is presented, which solves the atomic diffusion problem with xenon and krypton elements tramps produced by uranium fission during UO 2 nuclear fuel irradiation. The model considers intra and intergranular precipitation bubbles, its re dissolution owing to highly energetic fission products impact, interconnection of intergranular bubbles and gas sweeping by grain border in movement because of grain growth. In the model, the existence of a thermal gradient in the fuel pellet is considered, as well as temporal variations of fission rate owing to changes in the operation lineal power. The diffusion equation is solved by the finite element method and results of gas release and swelling calculation owing to gas fission are compared with experimental data. (author)

  3. Ideological Fission

    DEFF Research Database (Denmark)

    Christiansen, Steen Ledet

    ; it is a materialisation of an ideological fission which attempts to excise certain ideological constructions, yet paradoxically casting them in a form that is recognizable and familiar. The monstrous metonomy which is used shows us glimpses of a horrid being, intended to vilify the attack on New York City. However......, it is a being which is reminiscent of earlier monsters - from Godzilla to The Blob. It is evident that the Cloverfield monster is a paradoxical construction which attempts to articulate fear and loathing about terrorism, but ends up trapped in an ideological dead-end maze, unable to do anything other than...

  4. Is it possible at all to compare nuclear power plants and wind power systems?

    International Nuclear Information System (INIS)

    Eliasz, J.; Biwan, A.

    2005-01-01

    At first glance, it appears impossible to compare power generation technologies that are as different in their conception as nuclear power plants and wind power systems. On the other hand, if one uses a holistic approach it may be possible. The contribution lists the preconditions that are required, e.g. parameters like the life cycle of a technology, the various stages of modelling energy and mass exchange of subsystems, and the interactions between the various branches of a power generation technology. (orig.)

  5. Automated analysis for large amount gaseous fission product gamma-scanning spectra from nuclear power plant and its data mining

    International Nuclear Information System (INIS)

    Weihua Zhang; Kurt Ungar; Ian Hoffman; Ryan Lawrie; Jarmo Ala-Heikkila

    2010-01-01

    Based on the Linssi database and UniSampo/Shaman software, an automated analysis platform has been setup for the analysis of large amounts of gamma-spectra from the primary coolant monitoring systems of a CANDU reactor. Thus, a database inventory of gaseous and volatile fission products in the primary coolant of a CANDU reactor has been established. This database is comprised of 15,000 spectra of radioisotope analysis records. Records from the database inventory were retrieved by a specifically designed data-mining module and subjected to further analysis. Results from the analysis were subsequently used to identify the reactor coolant half-life of 135 Xe and 133 Xe, as well as the correlations of 135 Xe and 88 Kr activities. (author)

  6. Mica fission detectors

    International Nuclear Information System (INIS)

    Wong, C.; Anderson, J.D.; Hansen, L.; Lehn, A.V.; Williamson, M.A.

    1977-01-01

    The present development status of the mica fission detectors is summarized. It is concluded that the techniques have been refined and developed to a state such that the mica fission counters are a reliable and reproducible detector for fission events

  7. IFPE/NFIR-1, Clad creep-down, power history effect on fission product distribution (6 PWR rods 40-64 MWd/kg in BR-3)

    International Nuclear Information System (INIS)

    Turnbull, J.A.

    2006-01-01

    Description: The NFIR-1 programme was designed to investigate factors likely to affect the fission gas release behaviour of fuel rods operating under normal commercial conditions. The factors which were investigated were: - the effect of fuel/rod design parameters, e.g., wet versus dry route pellet manufacture, fuel-clad gap size and rod pressurization; - the effect of power history i.e., In/Out fuel management strategy; - the effect of burn-up extension. This was accomplished by an extensive PIE campaign on 6 fuel rods irradiated to 40-64 MWd/kg under different prescribed conditions in the BR3 PWR. The examination involved non destructive mensuration and destructive examination using optical, SEM, TEM and EPMA techniques. The dataset is unique in demonstrating the effect of these variables on fuel performance

  8. Experiments to determine the rate of beta energy release following fission of Pu239 andU235 in a fast reactor

    International Nuclear Information System (INIS)

    Murphy, M.F.; Taylor, W.H.; Sweet, D.W.; March, M.R.

    1979-02-01

    Measurements have been made of the rate of beta energy release from Pu239 and U235 fission fragments over a period of 107 seconds following a 105 second irradiation in the zero-power fast reactor Zebra. Results are compared with predictions using the UKFPDD-1 decay data file and two different sets of fission product yield data. (author)

  9. Physics and chemistry of fission

    International Nuclear Information System (INIS)

    1979-01-01

    Full text: In the pleasant and hospitable atmosphere of the Kernforschungsanlage Juelich in the Federal Republic of Germany, the IAEA symposium on the Physics and Chemistry of Fission took place. Almost 200 scientists attended, 154 abstracts were submitted, and 57 papers presented, but more important than the numbers was the quality of the contributions and the progress reported at the symposium. The neutron was discovered almost 50 years ago; 40 years ago the idea of nuclear fission was born. Since then, a number of laboratories have worked hard to explain the phenomenon of fission One would expect that by now scientists would know exactly what happens in a nucleus before and during the process of fission, particularly as there are hundreds of power and research reactors in operation, and fission of uranium isotopes is the basis of their functioning. At first glance, fission seems a simple process: a neutron hits and penetrates the uranium nucleus which becomes excited, i.e. has a surplus of energy. One way to get rid of this energy is for the nucleus to split into two parts; additional products of this process are energy and more neutrons. Nature, however, seems to dislike such straightforward explanations. In the case of fission, scientists have observed a number of phenomena which disagree with a simple model. Sometimes, a nucleus will split into two parts without being 'attacked' by a neutron; this spontaneous fission opens up a new line of fission research and several contributions at the symposium reported on sophisticated experiments designed to unravel some of its specific details. Sometimes, a fissioning nucleus will emit another particle: ternary fission has become a powerful tool for studying the properties of nuclei during the fission process. For the scientist, it is fascinating to observe how the nucleus behaves during fission. They invent models which are supposed to reproduce the most probable course of events leading to fission. In one of these

  10. Modelling isothermal fission gas release

    International Nuclear Information System (INIS)

    Uffelen, P. van

    2002-01-01

    The present paper presents a new fission gas release model consisting of two coupled modules. The first module treats the behaviour of the fission gas atoms in spherical grains with a distribution of grain sizes. This module considers single atom diffusion, trapping and fission induced re-solution of gas atoms associated with intragranular bubbles, and re-solution from the grain boundary into a few layers adjacent to the grain face. The second module considers the transport of the fission gas atoms along the grain boundaries. Four mechanisms are incorporated: diffusion controlled precipitation of gas atoms into bubbles, grain boundary bubble sweeping, re-solution of gas atoms into the adjacent grains and gas flow through open porosity when grain boundary bubbles are interconnected. The interconnection of the intergranular bubbles is affected both by the fraction of the grain face occupied by the cavities and by the balance between the bubble internal pressure and the hydrostatic pressure surrounding the bubbles. The model is under validation. In a first step, some numerical routines have been tested by means of analytic solutions. In a second step, the fission gas release model has been coupled with the FTEMP2 code of the Halden Reactor Project for the temperature distribution in the pellets. A parametric study of some steady-state irradiations and one power ramp have been simulated successfully. In particular, the Halden threshold for fission gas release and two simplified FUMEX cases have been computed and are summarised. (author)

  11. Fission theory and actinide fission data

    Energy Technology Data Exchange (ETDEWEB)

    Michaudon, A.

    1975-06-01

    The understanding of the fission process has made great progress recently, as a result of the calculation of fission barriers, using the Strutinsky prescription. Double-humped shapes were obtained for nuclei in the actinide region. Such shapes could explain, in a coherent manner, many different phenomena: fission isomers, structure in near-threshold fission cross sections, intermediate structure in subthreshold fission cross sections and anisotropy in the emission of the fission fragments. A brief review of fission barrier calculations and relevant experimental data is presented. Calculations of fission cross sections, using double-humped barrier shapes and fission channel properties, as obtained from the data discussed previously, are given for some U and Pu isotopes. The fission channel theory of A. Bohr has greatly influenced the study of low-energy fission. However, recent investigation of the yields of prompt neutrons and γ rays emitted in the resonances of {sup 235}U and {sup 239}Pu, together with the spin determination for many resonances of these two nuclei cannot be explained purely in terms of the Bohr theory. Variation in the prompt neutron and γ-ray yields from resonance to resonance does not seem to be due to such fission channels, as was thought previously, but to the effect of the (n,γf) reaction. The number of prompt fission neutrons and the kinetic energy of the fission fragments are affected by the energy balance and damping or viscosity effects in the last stage of the fission process, from saddle point to scission. These effects are discussed for some nuclei, especially for {sup 240}Pu.

  12. Comparative analysis of the application of different Low Power Wide Area Network technologies in power grid

    Science.gov (United States)

    Wang, Hao; Sui, Hong; Liao, Xing; Li, Junhao

    2018-03-01

    Low Power Wide Area Network (LPWAN) technologies developed rapidly in recent years, but the application principle of different LPWAN technologies in power grid is still not clear. This paper gives a comparative analysis of two mainstream LPWAN technologies including NB-IoT and LoRa, and gives an application suggestion of these two LPWAN technologies, which can guide the planning and construction of LPWAN in power grid.

  13. Tests to determine the release of short-lived fission products from UO2 fuel operating at linear powers of 45 and 60 kW/m

    International Nuclear Information System (INIS)

    Hastings, I.J.; Hunt, C.E.L.; Lipsett, J.J.; MacDonald, R.D.

    1985-09-01

    Experiments have been carried out using a 'sweep gas' technique to determine the behaviour of short-lived fission products within operating, intact UO 2 fuel elements. The Zircaloy-4-clad elements were 600 mm long and contained fuel of density 10.65 - 10.71 Mg/m 3 . A He-2% H 2 carrier gas swept gaseous or volatile fission products out of the operating fuel element past a gamma spectrometer for measurement. We outline our loop model and give full details of calculational procedures. In tests at linear powers of 45 (FIO-122) and 60 kW/m (FIO-124) to a maximum burnup of 80 MW.h/kg U, the species measured directly at the spectrometer during normal operation were generally the short-lived xenons and kryptons. Iodines were not observed during normal operation. The behaviour of I-133 and I-135 was deduced from the decay of Xe-133 and Xe-135 during reactor shutdowns. Plots of R/B (released/born) against λ (decay constant) or effective λ for all isotopes observed at 45 and 60 kW/m show that a line of slope -0.5, corresponding with diffusion kinetics, is a good fit to the measured xenon and krypton data. The inferred release of iodine fits the same line. From this we can extrapolate to an R/B for I-131 of about 5 x 10 -4 at 45 kW/m, and 3 x 10 -3 at 60 kW/m. Both tests were terminated by defects. Under defect conditions, R/B dependence on λ was about 0.6. I-131 release under defect conditions was 5 Ci and 60 mCi for FIO-122 and FI0-124, respectively. 22 refs

  14. Comparative analysis of existing models for power-grid synchronization

    International Nuclear Information System (INIS)

    Nishikawa, Takashi; Motter, Adilson E

    2015-01-01

    The dynamics of power-grid networks is becoming an increasingly active area of research within the physics and network science communities. The results from such studies are typically insightful and illustrative, but are often based on simplifying assumptions that can be either difficult to assess or not fully justified for realistic applications. Here we perform a comprehensive comparative analysis of three leading models recently used to study synchronization dynamics in power-grid networks—a fundamental problem of practical significance given that frequency synchronization of all power generators in the same interconnection is a necessary condition for a power grid to operate. We show that each of these models can be derived from first principles within a common framework based on the classical model of a generator, thereby clarifying all assumptions involved. This framework allows us to view power grids as complex networks of coupled second-order phase oscillators with both forcing and damping terms. Using simple illustrative examples, test systems, and real power-grid datasets, we study the inherent frequencies of the oscillators as well as their coupling structure, comparing across the different models. We demonstrate, in particular, that if the network structure is not homogeneous, generators with identical parameters need to be modeled as non-identical oscillators in general. We also discuss an approach to estimate the required (dynamical) system parameters that are unavailable in typical power-grid datasets, their use for computing the constants of each of the three models, and an open-source MATLAB toolbox that we provide for these computations. (paper)

  15. Electric power economy: comparative study of electric power consumption in many methods of outfloor control

    International Nuclear Information System (INIS)

    Kubota, Hideo; Tsitiya, Milton Tomoyuki

    1989-01-01

    This work presents a comparative study of the electric power consumption of a water elevatory station in order to verify which method is the most suitable in energy economy through the outflow variation in function of the demand

  16. Options for development of space fission propulsion systems

    International Nuclear Information System (INIS)

    Houts, Mike; Van Dyke, Melissa; Godfroy, Tom; Pedersen, Kevin; Martin, James; Dickens, Ricky; Salvail, Pat; Hrbud, Ivana

    2001-01-01

    Fission technology can enable rapid, affordable access to any point in the solar system. Potential fission-based transportation options include high specific power continuous impulse propulsion systems and bimodal nuclear thermal rockets. Despite their tremendous potential for enhancing or enabling deep space and planetary missions, to date space fission systems have only been used in Earth orbit. The first step towards utilizing advanced fission propulsion systems is development of a safe, near-term, affordable fission system that can enhance or enable near-term missions of interest. An evolutionary approach for developing space fission propulsion systems is proposed

  17. Two-Dimensional Mapping of the Calculated Fission Power for the Full-Size Fuel Plate Experiment Irradiated in the Advanced Test Reactor

    Science.gov (United States)

    Chang, G. S.; Lillo, M. A.

    2009-08-01

    The National Nuclear Security Administrations (NNSA) Reduced Enrichment for Research and Test Reactors (RERTR) program assigned to the Idaho National Laboratory (INL) the responsibility of developing and demonstrating high uranium density research reactor fuel forms to enable the use of low enriched uranium (LEU) in research and test reactors around the world. A series of full-size fuel plate experiments have been proposed for irradiation testing in the center flux trap (CFT) position of the Advanced Test Reactor (ATR). These full-size fuel plate tests are designated as the AFIP tests. The AFIP nominal fuel zone is rectangular in shape having a designed length of 21.5-in (54.61-cm), width of 1.6-in (4.064-cm), and uniform thickness of 0.014-in (0.03556-cm). This gives a nominal fuel zone volume of 0.482 in3 (7.89 cm3) per fuel plate. The AFIP test assembly has two test positions. Each test position is designed to hold 2 full-size plates, for a total of 4 full-size plates per test assembly. The AFIP test plates will be irradiated at a peak surface heat flux of about 350 W/cm2 and discharged at a peak U-235 burn-up of about 70 at.%. Based on limited irradiation testing of the monolithic (U-10Mo) fuel form, it is desirable to keep the peak fuel temperature below 250°C to achieve this, it will be necessary to keep plate heat fluxes below 500 W/cm2. Due to the heavy U-235 loading and a plate width of 1.6-in (4.064-cm), the neutron self-shielding will increase the local-to-average-ratio (L2AR) fission power near the sides of the fuel plates. To demonstrate that the AFIP experiment will meet the ATR safety requirements, a very detailed 2-dimensional (2D) Y-Z fission power profile was evaluated in order to best predict the fuel plate temperature distribution. The ability to accurately predict fuel plate power and burnup are essential to both the design of the AFIP tests as well as evaluation of the irradiated fuel performance. To support this need, a detailed MCNP Y

  18. Fusion-fission dynamics

    International Nuclear Information System (INIS)

    Blocki, J.; Planeta, R.; Brzychczyk, J.; Grotowski, K.

    1991-04-01

    Classical dynamical calculations of the heavy ion induced fission process for the reactions 40 Ar+ 141 Pr, 20 Ne+ 165 Ho and 12 C+ 175 Lu leading to the iridium like nucleus have been performed. As a result prescission lifetimes were obtained and compared with the experimental values. The agreement between the calculated and experimental lifetimes indicates that the one-body dissipation picture is much more relevant in describing the fusion-fission dynamics than the two-body one. Somewhat bigger calculated times than the experimental ones in case of the C+Lu reaction at 16 MeV/nucleon may be a signal on the energy range applicability of the one-body dissipation model. (author)

  19. Nuclear fission and reactions

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    The nuclear fission research programs are designed to elucidate basic features of the fission process. Specifically, (1) factors determining how nucleons of a fissioning nucleus are distributed between two fission fragments, (2) factors determining kinetic energy and excitation energies of fragments, and (3) factors controlling fission lifetimes. To these ends, fission studies are reported for several heavy elements and include investigations of spontaneous and neutron-induced fission, heavy ion reactions, and high energy proton reactions. The status of theoretical research is also discussed. (U.S.)

  20. Energy from nuclear fission()

    Science.gov (United States)

    Ripani, M.

    2015-08-01

    The main features of nuclear fission as physical phenomenon will be revisited, emphasizing its peculiarities with respect to other nuclear reactions. Some basic concepts underlying the operation of nuclear reactors and the main types of reactors will be illustrated, including fast reactors, showing the most important differences among them. The nuclear cycle and radioactive-nuclear-waste production will be also discussed, along with the perspectives offered by next generation nuclear assemblies being proposed. The current situation of nuclear power in the world, its role in reducing carbon emission and the available resources will be briefly illustrated.

  1. Measurements of fission yields

    International Nuclear Information System (INIS)

    Denschlag, H.O.

    2000-01-01

    After some historical introductory remarks on the discovery of nuclear fission and early fission yield determinations, the present status of knowledge on fission yields is briefly reviewed. Practical and fundamental reasons motivating the pursuit of fission yield measurements in the coming century are pointed out. Recent results and novel techniques are described that promise to provide new interesting insights into the fission process during the next century. (author)

  2. Radiochemical studies on fission

    Energy Technology Data Exchange (ETDEWEB)

    None

    1973-07-01

    Research progress is reported on nuclear chemistry; topics considered include: recoil range and kinetic energy distribution in the thermal neutron ftssion of /sup 245/Cm; mass distribution and recoil range measurements in the reactor neutron-induced fission of /sup 232/U; fission yields in the thermal neutron fission of /sup 241/PU highly asymmetric binary fission of uranium induced by reactor neutrons; and nuclear charge distribution in low energy fission. ( DHM)

  3. Gross greenhouse gas fluxes from hydro-power reservoir compared to thermo-power plants

    International Nuclear Information System (INIS)

    Santos, Marco Aurelio dos; Pinguelli Rosa, Luiz; Sikar, Bohdan; Sikar, Elizabeth; Santos, Ednaldo Oliveira dos

    2006-01-01

    This paper presents the findings of gross carbon dioxide and methane emissions measurements in several Brazilian hydro-reservoirs, compared to thermo power generation. The term 'gross emissions' means gas flux measurements from the reservoir surface without natural pre-impoundment emissions by natural bodies such as the river channel, seasonal flooding and terrestrial ecosystems. The net emissions result from deducting pre-existing emissions by the reservoir. A power dam emits biogenic gases such as CO 2 and CH 4 . However, studies comparing gas emissions (gross emissions) from the reservoir surface with emissions by thermo-power generation technologies show that the hydro-based option presents better results in most cases analyzed. In this study, measurements were carried in the Miranda, Barra Bonita, Segredo, Tres Marias, Xingo, and Samuel and Tucurui reservoirs, located in two different climatological regimes. Additional data were used here from measurements taken at the Itaipu and Serra da Mesa reservoirs. Comparisons were also made between emissions from hydro-power plants and their thermo-based equivalents. Bearing in mind that the estimated values for hydro-power plants include emissions that are not totally anthropogenic, the hydro-power plants studied generally posted lower emissions than their equivalent thermo-based counterparts. Hydro-power complexes with greater power densities (capacity/area flooded-W/m 2 ), such as Itaipu, Xingo, Segredo and Miranda, have the best performance, well above thermo-power plants using state-of-the-art technology: combined cycle fueled by natural gas, with 50% efficiency. On the other hand, some hydro-power complexes with low-power density perform only slightly better or even worse than their thermo-power counterparts

  4. The evaluation of failure stress and released amount of fission product gas of power ramped rod by fuel behaviour analysis code 'FEMAXI-III'

    International Nuclear Information System (INIS)

    Yanagisawa, Kazuaki; Fujita, Misao

    1984-01-01

    Pellet-Cladding Interaction(PCI) related in-pile failure of Zircaloy sheathed fuel rod is in general considered to be caused by combination of pellet-cladding mechanical interaction(PCMI) with fuel-cladding chemical interaction(FCCI). An understanding of a basic mechanism of PCI-related fuel failure is therefore necessary to get actual cladding hoop stress from mechanical interaction and released amounts of fission product(FP) gas of aggressive environmental agency from chemical interaction. This paper describes results of code analysis performed on fuel failure to cladding hoop stress and amounts of FP gas released under the condition associated with power ramping. Data from Halden(HBWR) and from Studsvik(R2) are used for code analysis. The fuel behaviour analysis code ''FEMAXI-III'' is used as an analytical tool. The followings are revealed from the study: (1) PCI-related fuel failure is dependent upon cladding hoop stress and released amounts of FP gas at power ramping. (2) Preliminary calculated threshold values of hoop stress and of released amounts of FP gas to PCI failure are respectively 330MPa, 10% under the Halden condition, 190MPa, 5% under the Inter ramp(BWR) condition, and 270MPa, 14% under the Over ramp(PWR) condition. The values of hoop stress calculated are almost in the similar range of those obtained from ex-reactor PCI simulated tests searched from references published. (3) The FEMAXI-III code verification is made in mechanical manner by using in-pile deformation data(diametral strain) obtained from power ramping test undertaken by JAERI. While, the code verification is made in thermal manner by using punctured FP gas data obtained from post irradiation examination performed on non-defected power ramped fuel rods. The calculations are resulted in good agreements to both, mechanical and thermal experimental data suggesting the validity of the code evaluation. (J.P.N.)

  5. Muon induced fission and fission track dating of minerals

    International Nuclear Information System (INIS)

    Marques, A.

    1988-01-01

    The effects of muon induced fission on geological dating of samples by the fission track method are evaluated for the case of muscovite minerals. It is found a small but significant effect, greater for the longer ages. Since calculations are developped under the hypothesis of constant atmosphere and primary cosmic ray flux it is suggested that any discrepancy found in ages of very old material that cannot be accounted for by well known environmental influences, be taken as an indication of variation on either the atmospheric stopping power or the intensity of cosmic radiation along the ages. (author) [pt

  6. Mirror hybrid (fusion--fission) reactor

    International Nuclear Information System (INIS)

    Bender, D.J.; Lee, J.D.; Neef, W.S.; Devoto, R.S.; Galloway, T.R.; Fink, J.H.; Schultz, K.R.; Culver, D.; Rao, S.

    1977-10-01

    The reference mirror hybrid reactor design performed by LLL and General Atomic is summarized. The reactor parameters have been chosen to minimize the cost of producing fissile fuel for consumption in fission power reactors. As in the past, we have emphasized the use of existing technology where possible and a minimum extrapolation of technology otherwise. The resulting reactor may thus be viewed as a comparatively near-term goal of the fusion program, and we project improved performance for the hybrid in the future as more advanced technology becomes available

  7. Nuclear fission with inertial confinement

    CERN Document Server

    Koshkarev, D G

    2002-01-01

    The possibility of initiating the explosive fission reaction in a small quantity of fissile material through the heavy ions beam from the powerful accelerator-driver, developed for realization of the thermonuclear synthesis in the deuterium-tritium cylindrical targets with the direct ignition, is considered. The consequences of applying this method in the nuclear engineering are discussed

  8. British and Italian electric power systems: Comparative study

    International Nuclear Information System (INIS)

    Lolli, A.

    1992-01-01

    This study compares the new electricity system in England, Wales and Scotland, after the 1989 Electricity Act, and the Italian electricity system (as modified by the January, 9, 1991, Law No. 9 and by the December 5, 1991, Decree No. 386 made law (No. 35) on January, 29, 1992). The study focuses on legal aspects and socio-economic factors influencing planning and organizing by the national electric power industries in their efforts to maintain supply and demand equilibrium

  9. Modelling of thermal mechanical behaviour of high burn-Up VVER fuel at power transients with special emphasis on the impact of fission gas induced swelling of fuel pellets

    International Nuclear Information System (INIS)

    Novikov, V.; Medvedev, A.; Khvostov, G.; Bogatyr, S.; Kuzetsov, V.; Korystin, L.

    2005-01-01

    This paper is devoted to the modelling of unsteady state mechanical and thermo-physical behaviour of high burn-up VVER fuel at a power ramp. The contribution of the processes related to the kinetics of fission gas to the consequences of pellet-clad mechanical interaction is analysed by the example of integral VVER-440 rod 9 from the R7 experimental series, with a pellet burn-up in the active part at around 60 MWd/kgU. This fuel rod incurred ramp testing with a ramp value ΔW 1 ∼ 250 W/cm in the MIR research reactor. The experimentally revealed residual deformation of the clad by 30-40 microns in the 'hottest' portion of the rod, reaching a maximum linear power of up to 430 W/cm, is numerically justified on the basis of accounting for the unsteady state swelling and additional degradation of fuel thermal conductivity due to temperature-induced formation and development of gaseous porosity within the grains and on the grain boundaries. The good prediction capability of the START-3 code, coupled with the advanced model of fission gas related processes, with regard to the important mechanical (residual deformation of clad, pellet-clad gap size, central hole filling), thermal physical (fission gas release) and micro-structural (profiles of intra-granular concentration of the retained fission gas and fuel porosity across a pellet) consequences of the R7 test is shown. (authors)

  10. Simulations of fusion chamber dynamics and first wall response in a Z-pinch driven fusion–fission hybrid power reactor (Z-FFR)

    Energy Technology Data Exchange (ETDEWEB)

    Qi, J.M., E-mail: qjm06@sina.com [Laboratory of Advanced Nuclear Energy (LANE), Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999 (China); Center for Fusion Energy Science and Technology (CFEST), China Academy of Engineering Physics, Mianyang 621999 (China); Wang, Z., E-mail: wangz_es@caep.cn [Laboratory of Advanced Nuclear Energy (LANE), Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999 (China); Center for Fusion Energy Science and Technology (CFEST), China Academy of Engineering Physics, Mianyang 621999 (China); Chu, Y.Y., E-mail: chuyanyun@caep.cn [Laboratory of Advanced Nuclear Energy (LANE), Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999 (China); Center for Fusion Energy Science and Technology (CFEST), China Academy of Engineering Physics, Mianyang 621999 (China); Li, Z.H., E-mail: lee_march@sina.com [Laboratory of Advanced Nuclear Energy (LANE), Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999 (China)

    2016-03-15

    Highlights: • Z-FFR utilizes DT neutrons to drive a sub-critical fission blanket to produce energy. • A metal shell and Ar gas are employed in the fusion chamber for shock mitigation. • Massive materials can effectively mitigate the thermal heats on the chamber wall. • The W-coated Zr-alloy first wall exhibits good viability as a long-lived component. - Abstract: In a Z-pinch driven fusion–fission hybrid power reactor (Z-FFR), the fusion target will produce enormous energy of ∼1.5 GJ per pulse at a frequency of 0.1 Hz. Almost 20% of the fusion energy yield, approximately 300 MJ, is released in forms of pulsed X-rays. To prevent the first wall from fatal damages by the intense X-rays, a thin spherical metal shell and rare Ar buffer gas are introduced to mitigate the transient X-ray bursts. Radiation hydrodynamics in the fusion chamber were investigated by MULTI-1D simulations, and the corresponding thermal and mechanical loads on the first wall were also obtained. The simulations indicated that by optimizing the design parameters of the metal shell and Ar buffer gas, peak power flux of the thermal heats on the first wall could be mitigated to less than 10{sup 4} W/cm{sup 2} within a time scale of several milliseconds, while peak overpressures of the mechanical loads varying from 0.6 to 0.7 MPa. In addition, the thermomechanical response in a W–coated Zr-alloy first wall was performed by FWDR1D calculations using the derived thermal and mechanical loads as inputs. The temperature and stress fields were analyzed, and the corresponding elastic strains were conducted for primary lifetime estimations by using the Coffin–Manson relationships of both W and Zr-alloy. It was shown that the maximum temperature rises and stresses in the first wall were less than 50 K and 130 MPa respectively, and lifetime of the first wall would be in excess of 10{sup 9} cycles. The chamber exhibits good viability as a long-lived component to sustain the Z-FFR conceptual

  11. A compound refining system for separation of gaseous fission products incorporated in a reprocessing pilot plant for spent fuel from neclear power stations

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    In the V. G. Khlopin Radium Institute, a gas treatment experimental apparatus was installed to the SU-2 type experimental facility. The purpose is to solve variety of problems in the separation, collection and subsequent treatment for gaseous fission products and highly volatile fission products in spent fuel reprocessing. The experimental apparatus has the functions as follows: the measurement of air flow such as flow rate, pressure, total γ activity and krypton-85 content, preliminary air flow cleaning and drying removing aerosol, hydrogen fluoride and nitrogen oxide, and the trapping and analysis of gaseous fission products and highly volatile fission products in air flow. For the collection of these two types of fission products, a liquid absorbent and a solid adsorbent are used in series arrangement. (J.P.N.)

  12. Fission gas release behaviour in MOX fuels

    International Nuclear Information System (INIS)

    Viswanathan, U.K.; Anantharaman, S.; Sahoo, K.C.

    2002-01-01

    As a part of plutonium recycling programme MOX (U,Pu)O 2 fuels will be used in Indian boiling water reactors (BWR) and pressurised heavy water reactors (PHWR). Based on successful test irradiation of MOX fuel in CIRUS reactor, 10 MOX fuel assemblies have been loaded in the BWR of Tarapur Atomic Power Station (TAPS). Some of these MOX fuel assemblies have successfully completed the initial target average burnup of ∼16,000 MWD/T. Enhancing the burnup target of the MOX fuels and increasing loading of MOX fuels in TAPS core will depend on the feedback information generated from the measurement of released fission gases. Fission gas release behaviour has been studied in the experimental MOX fuel elements (UO 2 - 4% PuO 2 ) irradiated in pressurised water loop (PWL) of CIRUS. Eight (8) MOX fuel elements irradiated to an average burnup of ∼16,000 MWD/T have been examined. Some of these fuel elements contained controlled porosity pellets and chamfered pellets. This paper presents the design details of the experimental set up for studying fission gas release behaviour including measurement of gas pressure, void volume and gas composition. The experimental data generated is compared with the prediction of fuel performance modeling codes of PROFESS and GAPCON THERMAL-3. (author)

  13. Fission cross section calculations for 209Bi target nucleus based on fission reaction models in high energy regions

    Directory of Open Access Journals (Sweden)

    Kaplan Abdullah

    2015-01-01

    Full Text Available Implementation of projects of new generation nuclear power plants requires the solving of material science and technological issues in developing of reactor materials. Melts of heavy metals (Pb, Bi and Pb-Bi due to their nuclear and thermophysical properties, are the candidate coolants for fast reactors and accelerator-driven systems (ADS. In this study, α, γ, p, n and 3He induced fission cross section calculations for 209Bi target nucleus at high-energy regions for (α,f, (γ,f, (p,f, (n,f and (3He,f reactions have been investigated using different fission reaction models. Mamdouh Table, Sierk, Rotating Liquid Drop and Fission Path models of theoretical fission barriers of TALYS 1.6 code have been used for the fission cross section calculations. The calculated results have been compared with the experimental data taken from the EXFOR database. TALYS 1.6 Sierk model calculations exhibit generally good agreement with the experimental measurements for all reactions used in this study.

  14. Nuclear fission with a Langevin equation

    International Nuclear Information System (INIS)

    Boilley, D.; Suraud, E.; Abe, Yasuhisa

    1992-01-01

    A microscopically derived Langevin equation is applied to thermally induced nuclear fission. An important memory effect is pointed out and discussed. A strong friction coefficient, estimated from microscopic quantities, tends to decrease the stationary limit of the fission rate and to increase the transient time. The calculations are performed with a collective mass depending on the collective variable and with a constant mass. Fission rates calculated at different temperatures are shown and compared with previous available results. (author) 23 refs.; 7 figs

  15. Energy released in fission

    International Nuclear Information System (INIS)

    James, M.F.

    1969-05-01

    The effective energy released in and following the fission of U-235, Pu-239 and Pu-241 by thermal neutrons, and of U-238 by fission spectrum neutrons, is discussed. The recommended values are: U-235 ... 192.9 ± 0.5 MeV/fission; U-238 ... 193.9 ± 0.8 MeV/fission; Pu-239 ... 198.5 ± 0.8 MeV/fission; Pu-241 ... 200.3 ± 0.8 MeV/fission. These values include all contributions except from antineutrinos and very long-lived fission products. The detailed contributions are discussed, and inconsistencies in the experimental data are pointed out. In Appendix A, the contribution to the total useful energy release in a reactor from reactions other than fission are discussed briefly, and in Appendix B there is a discussion of the variations in effective energy from fission with incident neutron energy. (author)

  16. JNDC nuclear data library of fission products

    International Nuclear Information System (INIS)

    Tasaka, Kanji; Ihara, Hitoshi; Akiyama, Masatsugu; Yoshida, Tadashi; Matumoto, Zyun-itiro; Nakasima, Ryuzo

    1983-10-01

    The JNDC (Japanese Nuclear Data Committee) FP (Fission Product) nuclear data library for 1172 fission products is described in this report. The gross theory of beta decay has been used extensively for estimating unknown decay data and also some of known decay data with poor accuracy. The calculated decay powers of fission products using the present library show excellent agreement with the latest measurements at ORNL (Oak Ridge National Laboratory), LANL (Los Alamos National Laboratory) and UTT (University of Tokyo, Tokai) for cooling times shorter than 10 3 s after irradiation. The calculated decay powers by the existing libraries showed systematic deviations at short cooling times; the calculated beta and gamma decay powers after burst fission were smaller than the experimental results for cooling times shorter than 10 s, and in the cooling time range 10 to 10 3 s the beta-decay power was larger than the measured values and the gamma decay power smaller than the measured results. The present JNDC FP nuclear data library resolved these discrepancies in the short cooling time ranges. The decay power of fission products has been calculated for ten fission types and the results have been fitted by an analytical function with 31 exponentials. This permits the easy application of the present results of decay power calculations to a LOCA (Loss-of-Coolant Accident) analysis of a light water reactor and so on. (author)

  17. Fission yield covariance generation and uncertainty propagation through fission pulse decay heat calculation

    International Nuclear Information System (INIS)

    Fiorito, L.; Diez, C.J.; Cabellos, O.; Stankovskiy, A.; Van den Eynde, G.; Labeau, P.E.

    2014-01-01

    Highlights: • Fission yield data and uncertainty comparison between major nuclear data libraries. • Fission yield covariance generation through Bayesian technique. • Study of the effect of fission yield correlations on decay heat calculations. • Covariance information contribute to reduce fission pulse decay heat uncertainty. - Abstract: Fission product yields are fundamental parameters in burnup/activation calculations and the impact of their uncertainties was widely studied in the past. Evaluations of these uncertainties were released, still without covariance data. Therefore, the nuclear community expressed the need of full fission yield covariance matrices to be able to produce inventory calculation results that take into account the complete uncertainty data. State-of-the-art fission yield data and methodologies for fission yield covariance generation were researched in this work. Covariance matrices were generated and compared to the original data stored in the library. Then, we focused on the effect of fission yield covariance information on fission pulse decay heat results for thermal fission of 235 U. Calculations were carried out using different libraries and codes (ACAB and ALEPH-2) after introducing the new covariance values. Results were compared with those obtained with the uncertainty data currently provided by the libraries. The uncertainty quantification was performed first with Monte Carlo sampling and then compared with linear perturbation. Indeed, correlations between fission yields strongly affect the uncertainty of decay heat. Eventually, a sensitivity analysis of fission product yields to fission pulse decay heat was performed in order to provide a full set of the most sensitive nuclides for such a calculation

  18. HAC and fission reactors

    International Nuclear Information System (INIS)

    Fujiwara, I.; Moriyama, H.; Tachikawa, E.

    1984-01-01

    In the fission process, newly formed fission products undergo hot atom reactions due to their energetic recoil and abnormal positive charge. The hot atom reactions of the fission products are usually accompanied by secondary effects such as radiation damage, especially in condensed phase. For reactor safety it is valuable to know the chemical behaviour and the release behaviour of these radioactive fission products. Here, the authors study the chemical behaviour and the release behaviour of the fission products from the viewpoint of hot atom chemistry (HAC). They analyze the experimental results concerning fission product behaviour with the help of the theories in HAC and other neighboring fields such as radiation chemistry. (Auth.)

  19. Cumulative fission yield of Ce-148 produced by thermal-neutron fission of U-235

    International Nuclear Information System (INIS)

    Hasan, A.A.

    1984-12-01

    Cumulative fission yield of 148 cesium isotopes and some other fission products produced by thermal-neutron fission of 235 uranium is determined by Germanium/Lithium spectroscopic methods. The measuremets were done at Tsing-Hua open pool reactor using 3 to 4 mg of 93.15% enriched 235 uranium samples. Gamma rays are assigned to the responsible fission products by matching gamma rays energies and half lives. Fission rate is calculated by fission track method. Cumulative fission yields of 148 cesium, 90 krypton, 130 iodine, 144 lanthanum, 89 krypton, 136 xenon, 137 xenon and 140 cesium are calculated. This values are compared with previously predicted values and showed good agreement. 21 Ref

  20. The potential of fission nuclear power in resolving global climate change under the constraints of nuclear fuel resources and once-through fuel cycles

    International Nuclear Information System (INIS)

    Knapp, Vladimir; Pevec, Dubravko; Matijevic, Mario

    2010-01-01

    Nuclear fission is receiving new attention as a developed source of carbon-free energy. A much larger number of nuclear reactors would be needed for a major impact on carbon emission. The crucial question is whether it can be done without increasing the risk of nuclear proliferation. Specifically, can a larger nuclear share in world energy production, well above the present 6%, be achieved in the next few decades without adding the proliferation-sensitive technologies of reprocessing spent fuel and recycling plutonium to the problems of the unavoidable use of enrichment technology? The answer depends on the available uranium resources. We first looked for the maximum possible nuclear build-up in the 2025-2065 period under the constraints of the estimated uranium resources and the use of once-through nuclear fuel technology. Our results show that nuclear energy without reprocessing could reduce carbon emission by 39.6% of the total reduction needed to bring the WEO 2009 Reference Scenario prediction of total GHG emissions in 2065 to the level of the WEO 450 Scenario limiting global temperature increase to 2 deg. C. The less demanding strategy of the nuclear replacement of all non-CCS coal power plants retiring during the 2025-2065 period would reduce emission by 26.1%.

  1. Studies of fission fragment yields via high-resolution γ-ray spectroscopy

    Science.gov (United States)

    Wilson, J. N.; Lebois, M.; Qi, L.; Amador-Celdran, P.; Bleuel, D.; Briz, J. A.; Carroll, R.; Catford, W.; Witte, H. De; Doherty, D. T.; Eloirdi, R.; Georgiev, G.; Gottardo, A.; Goasduff, A.; Hadyñska-Klek, K.; Hauschild, K.; Hess, H.; Ingeberg, V.; Konstantinopoulos, T.; Ljungvall, J.; Lopez-Martens, A.; Lorusso, G.; Lozeva, R.; Lutter, R.; Marini, P.; Matea, I.; Materna, T.; Mathieu, L.; Oberstedt, A.; Oberstedt, S.; Panebianco, S.; Podolyak, Zs.; Porta, A.; Regan, P. H.; Reiter, P.; Rezynkina, K.; Rose, S. J.; Sahin, E.; Seidlitz, M.; Serot, O.; Shearman, R.; Siebeck, B.; Siem, S.; Smith, A. G.; Tveten, G. M.; Verney, D.; Warr, N.; Zeiser, F.; Zielinska, M.

    2018-03-01

    Precise spectroscopic information on the fast neutron induced fission of the 238U(n,f) reaction was recently gained using a new technique which involved coupling of the Miniball high resolution y-ray spectrometer and the LICORNE directional neutron source. The experiment allowed measurement of the isotopic fission yields for around 40 even-even nuclei at an incident neutron energy of around 2 MeV where yield data are very sparse. In addition spectroscopic information on very neutron-rich fission products was obtained. Results were compared to models, both the JEFF-3.1.1 data base and the GEF code, and large discrepancies for the S1 fission mode in the Sn/Mo isotope pair were discovered. This suggests that current models are overestimating the role played by spherical shell effects in fast neutron induced fission. In late 2017 and 2018 the nu-ball hybrid spectrometer will be constructed at the IPN Orsay to perform further experimental investigations with directional neutrons coupled to a powerful hybrid Ge/LaBr3 detector array. This will open up new possibilities for measurements of fission yields for fast-neutron-induced fission using the spectroscopic technique and will be complimentary to other methods being developed.

  2. Studies of fission fragment yields via high-resolution γ-ray spectroscopy

    Directory of Open Access Journals (Sweden)

    Wilson J.N.

    2018-01-01

    Full Text Available Precise spectroscopic information on the fast neutron induced fission of the 238U(n,f reaction was recently gained using a new technique which involved coupling of the Miniball high resolution y-ray spectrometer and the LICORNE directional neutron source. The experiment allowed measurement of the isotopic fission yields for around 40 even-even nuclei at an incident neutron energy of around 2 MeV where yield data are very sparse. In addition spectroscopic information on very neutron-rich fission products was obtained. Results were compared to models, both the JEFF-3.1.1 data base and the GEF code, and large discrepancies for the S1 fission mode in the Sn/Mo isotope pair were discovered. This suggests that current models are overestimating the role played by spherical shell effects in fast neutron induced fission. In late 2017 and 2018 the nu-ball hybrid spectrometer will be constructed at the IPN Orsay to perform further experimental investigations with directional neutrons coupled to a powerful hybrid Ge/LaBr3 detector array. This will open up new possibilities for measurements of fission yields for fast-neutron-induced fission using the spectroscopic technique and will be complimentary to other methods being developed.

  3. Status of fission product yield data

    International Nuclear Information System (INIS)

    Cuninghame, J.G.

    1978-01-01

    The topics covered in this paper are: (a) cumulative yields in thermal neutron fission and in fast fission up to 14 MeV incident neutron energy, (b) dependence of the yields on incident neutron energy and spectrum, (c) independent yields, (d) charge dispersion and distribution, and (e) yields of light particles from ternary fission. The paper reviews information on these subjects for fission of actinides from 232 Th upwards with special emphasis on data published since the 1973 Bologna FPND Panel, compares data sets, and discusses the gaps still to be found in them. (author)

  4. Possible emission of radioactive fission products during off-design accidents at a nuclear power plant with VVER-1000 reactor

    International Nuclear Information System (INIS)

    Dubkov, A.P.; Kozlov, V.F.; Luzanova, L.M.

    1995-01-01

    It is well known that eight nuclear power plants with VVER-1000 reactors have been constructed in Russia, Ukraine, and in the Republic of Belarus and they have been operating successfully without any serious accidents since 1980. These facilities have been analyzed for various accident scenarios, and measures have been incorporated which will prevent core damage during these possible events. However, an off-design accident can occur, and in such a case, the radiological consequences would exceed the worst design accidents. This paper reviews a number of potential off-design accidents in order to develop an accident plan to mitigate the consequences of such an accident

  5. Fission fragment angular distributions and fission cross section validation

    International Nuclear Information System (INIS)

    Leong, Lou Sai

    2013-01-01

    The present knowledge of angular distributions of neutron-induced fission is limited to a maximal energy of 15 MeV, with large discrepancies around 14 MeV. Only 238 U and 232 Th have been investigated up to 100 MeV in a single experiment. The n-TOF Collaboration performed the fission cross section measurement of several actinides ( 232 Th, 235 U, 238 U, 234 U, 237 Np) at the n-TOF facility using an experimental set-up made of Parallel Plate Avalanche Counters (PPAC), extending the energy domain of the incident neutron above hundreds of MeV. The method based on the detection of the 2 fragments in coincidence allowed to clearly disentangle the fission reactions among other types of reactions occurring in the spallation domain. I will show the methods we used to reconstruct the full angular resolution by the tracking of fission fragments. Below 10 MeV our results are consistent with existing data. For example in the case of 232 Th, below 10 MeV the results show clearly the variation occurring at the first (1 MeV) and second (7 MeV) chance fission, corresponding to transition states of given J and K (total spin and its projection on the fission axis), and a much more accurate energy dependence at the 3. chance threshold (14 MeV) has been obtained. In the spallation domain, above 30 MeV we confirm the high anisotropy revealed in 232 Th by the single existing data set. I'll discuss the implications of this finding, related to the low anisotropy exhibited in proton-induced fission. I also explore the critical experiments which is valuable checks of nuclear data. The 237 Np neutron-induced fission cross section has recently been measured in a large energy range (from eV to GeV) at the n-TOF facility at CERN. When compared to previous measurements, the n-TOF fission cross section appears to be higher by 5-7 % beyond the fission threshold. To check the relevance of n-TOF data, we simulate a criticality experiment performed at Los Alamos with a 6 kg sphere of 237 Np. This

  6. Utilization of fission reactors for fusion engineering testing

    International Nuclear Information System (INIS)

    Deis, G.A.; Miller, L.G.

    1985-01-01

    Fission reactors can be used to conduct some of the fusion nuclear engineering tests identified in the FINESSE study. To further define the advantages and disadvantages of fission testing, the technical and programmatic constraints on this type of testing are discussed here. This paper presents and discusses eight key issues affecting fission utilization. Quantitative comparisons with projected fusion operation are made to determine the technical assets and limitations of fission testing. Capabilities of existing fission reactors are summarized and compared with technical needs. Conclusions are then presented on the areas where fission testing can be most useful

  7. Roles of plasma neutron source reactor in development of fusion reactor engineering: Comparison with fission reactor engineering

    International Nuclear Information System (INIS)

    Hirayama, Shoichi; Kawabe, Takaya

    1995-01-01

    The history of development of fusion power reactor has come to a turning point, where the main research target is now shifting from the plasma heating and confinement physics toward the burning plasma physics and reactor engineering. Although the development of fusion reactor system is the first time for human beings, engineers have experience of development of fission power reactor. The common feature between them is that both are plants used for the generation of nuclear reactions for the production of energy, nucleon, and radiation on an industrial scale. By studying the history of the development of the fission reactor, one can find the existence of experimental neutron reactors including irradiation facilities for fission reactor materials. These research neutron reactors played very important roles in the development of fission power reactors. When one considers the strategy of development of fusion power reactors from the points of fusion reactor engineering, one finds that the fusion neutron source corresponds to the neutron reactor in fission reactor development. In this paper, the authors discuss the roles of the plasma-based neutron source reactors in the development of fusion reactor engineering, by comparing it with the neutron reactors in the history of fission power development, and make proposals for the strategy of the fusion reactor development. 21 refs., 6 figs

  8. Fission Research at IRMM

    Directory of Open Access Journals (Sweden)

    Al-Adili A.

    2010-03-01

    Full Text Available Fission Research at JRC-IRMM has a longstanding tradition. The present paper is discussing recent investigations of fission fragment properties of 238 U(n,f, 234 U(n,f, prompt neutron emission in fission of 252 Cf(SF as well as the prompt fission neutron spectrum of 235 U(n,f and is presenting the most important results.

  9. Health and safety: Preliminary comparative assessment of the Satellite Power System (SPS) and other energy alternatives

    Science.gov (United States)

    Habegger, L. J.; Gasper, J. R.; Brown, C.

    1980-01-01

    Data readily available from the literature were used to make an initial comparison of the health and safety risks of a fission power system with fuel reprocessing; a combined-cycle coal power system with a low-Btu gasifier and open-cycle gas turbine; a central-station, terrestrial, solar photovoltaic power system; the satellite power system; and a first-generation fusion system. The assessment approach consists of the identification of health and safety issues in each phase of the energy cycle from raw material extraction through electrical generation, waste disposal, and system deactivation; quantitative or qualitative evaluation of impact severity; and the rating of each issue with regard to known or potential impact level and level of uncertainty.

  10. Equilibrium fission model calculations

    International Nuclear Information System (INIS)

    Beckerman, M.; Blann, M.

    1976-01-01

    In order to aid in understanding the systematics of heavy ion fission and fission-like reactions in terms of the target-projectile system, bombarding energy and angular momentum, fission widths are calculated using an angular momentum dependent extension of the Bohr-Wheeler theory and particle emission widths using angular momentum coupling

  11. Economic analysis to compare fabrication of nuclear power and fossil fuel power plants at Iran

    International Nuclear Information System (INIS)

    Rasouliye Koohi, Mojtaba

    1997-01-01

    Electric power due to its many advantages over other forms of energies covers most of the world's energy demands.The electric power can be produced by various energy converting systems fed by different energy resources like fossil fuels, nuclear, hydro and renewable energies, each having their own appropriate technologies. The fossil fuel not only consumes the deplete and precious sources of non conventional energies but they add pollution to environment too. The nuclear power plants has its own share of radioactive pollutions which, of course can be controlled by taking precautionary measures. The investing cost of each generated unit (KWh) in the nuclear power plants, comparing with its equivalent production by fossil fuels is investigated. The various issues of economical analysis, technical, political and environmental are the different aspects, which individually can influence the decisions for kind of power plant to be installed. Finally, it is concluded that the fossil and nuclear power generations both has its own advantages and disadvantages. Hence, from a specializing point of view, it may not be proper to prefer one over the others

  12. Fission rate measurements in fuel plate type assembly reactor cores

    International Nuclear Information System (INIS)

    Rogers, J.W.

    1988-01-01

    The methods, materials and equipment have been developed to allow extensive and precise measurement of fission rate distributions in water moderated, U-Al fuel plate assembly type reactor cores. Fission rate monitors are accurately positioned in the reactor core, the reactor is operated at a low power for a short time, the fission rate monitors are counted with detectors incorporating automated sample changers and the measurements are converted to fission rate distributions. These measured fission rate distributions have been successfully used as baseline information related to the operation of test and experimental reactors with respect to fission power and distribution, fuel loading and fission experiments for approximately twenty years at the Idaho National Engineering Laboratory (INEL). 7 refs., 8 figs

  13. 14. International workshop on nuclear fission physics. Proceedings

    International Nuclear Information System (INIS)

    2000-01-01

    The meetings on nuclear fission took place 12-15 October 1998 and was organized by Institute of Physics and Power Engineering. The aim of the workshop was to present and discuss main new both theoretical and experimental results obtained in the area of nuclear fission, dynamical feature, properties of fission fragments and complementary radiation. As usual the program of the workshop was designed to cover a wide range of physical phenomena - from low energy and spontaneous fission to fission of hot rotating nuclei and multifragmentation at intermediate and high energies. Reaction induced by slow and fast neutron, light and heavy ions were discussed [ru

  14. Advanced fission and fossil plant economics-implications for fusion

    International Nuclear Information System (INIS)

    Delene, J.G.

    1994-01-01

    In order for fusion energy to be a viable option for electric power generation, it must either directly compete with future alternatives or serve as a reasonable backup if the alternatives become unacceptable. This paper discusses projected costs for the most likely competitors with fusion power for baseload electric capacity and what these costs imply for fusion economics. The competitors examined include advanced nuclear fission and advanced fossil-fired plants. The projected costs and their basis are discussed. The estimates for these technologies are compared with cost estimates for magnetic and inertial confinement fusion plants. The conclusion of the analysis is that fusion faces formidable economic competition. Although the cost level for fusion appears greater than that for fission or fossil, the costs are not so high as to preclude fusion's potential competitiveness

  15. NEACRP thermal fission product benchmark

    International Nuclear Information System (INIS)

    Halsall, M.J.; Taubman, C.J.

    1989-09-01

    The objective of the thermal fission product benchmark was to compare the range of fission product data in use at the present time. A simple homogeneous problem was set with 200 atoms H/1 atom U235, to be burnt up to 1000 days and then decay for 1000 days. The problem was repeated with 200 atoms H/1 atom Pu239, 20 atoms H/1 atom U235 and 20 atoms H/1 atom Pu239. There were ten participants and the submissions received are detailed in this report. (author)

  16. Consistent dynamical and statistical description of fission and comparison

    Energy Technology Data Exchange (ETDEWEB)

    Shunuan, Wang [Chinese Nuclear Data Center, Beijing, BJ (China)

    1996-06-01

    The research survey of consistent dynamical and statistical description of fission is briefly introduced. The channel theory of fission with diffusive dynamics based on Bohr channel theory of fission and Fokker-Planck equation and Kramers-modified Bohr-Wheeler expression according to Strutinsky method given by P.Frobrich et al. are compared and analyzed. (2 figs.).

  17. Prompt fission neutron spectra of n + 235U above the (n, nf) fission threshold

    International Nuclear Information System (INIS)

    Shu Nengchuan; Chen Yongjing; Liu Tingjin; Jia Min

    2015-01-01

    Calculations of prompt fission neutron spectra (PFNS) from the 235 U(n, f) reaction were performed with a semi-empirical method for En = 7.0 and 14.7 MeV neutron energies. The total PFNS were obtained as a superposition of (n, xnf) pre-fission neutron spectra and post-fission spectra of neutrons which were evaporated from fission fragments, and these two kinds of spectra were taken as an expression of the evaporation spectrum. The contributions of (n, xnf) fission neutron spectra on the calculated PFNS were discussed. The results show that emission of one or two neutrons in the (n, nf) or (n, 2nf) reactions influences the PFNS shape, and the neutron spectra of the (n, xnf) fission-channel are soft compared with the neutron spectra of the (n, f) fission channel. In addition, analysis of the multiple-chance fission component showed that second-chance fission dominates the PFNS with an incident neutron energy of 14.7 MeV whereas first-chance fission dominates the 7 MeV case. (authors)

  18. Mass dependence of positive pion-induced fission

    International Nuclear Information System (INIS)

    Khan, H.A.; Khan, N.A.; Peterson, R.J.

    1991-01-01

    Fission cross sections for a range of targets have been measured by solid-state track detectors following 80 and 100 MeV π + bombardment. Fission probabilities have been inferred by comparison to computed reaction cross sections. Fission probabilities for heavy targets agree with those for other probes of comparable energy and with statistical calculations. Probabilities for lighter targets are much above those previously observed or computed. Ternary fission cross sections and multiplicities of light fragments have also been determined

  19. Fission products in National Atmospheric Deposition Program—Wet deposition samples prior to and following the Fukushima Dai-Ichi Nuclear Power Plant incident, March 8?April 5, 2011

    Science.gov (United States)

    Wetherbee, Gregory A.; Debey, Timothy M.; Nilles, Mark A.; Lehmann, Christopher M.B.; Gay, David A.

    2012-01-01

    Radioactive isotopes I-131, Cs-134, or Cs-137, products of uranium fission, were measured at approximately 20 percent of 167 sampled National Atmospheric Deposition Program monitoring sites in North America (primarily in the contiguous United States and Alaska) after the Fukushima Dai-Ichi Nuclear Power Plant incident on March 12, 2011. Samples from the National Atmospheric Deposition Program were analyzed for the period of March 8-April 5, 2011. Calculated 1- or 2-week radionuclide deposition fluxes at 35 sites from Alaska to Vermont ranged from 0.47 to 5,100 Becquerels per square meter during the sampling period of March 15-April 5, 2011. No fission-product isotopes were measured in National Atmospheric Deposition Program samples obtained during March 8-15, 2011, prior to the arrival of contaminated air in North America.

  20. The fast fission effect in a cylindrical fuel element

    Energy Technology Data Exchange (ETDEWEB)

    Carlvik, I; Pershagen, B

    1959-06-15

    A new formula for the fast fission factor is derived, which takes proper account to fast capture. The fission neutron spectrum is divided into two groups with constant fission cross section in one group and zero fission cross section in the other. The average total, elastic, inelastic and capture cross sections in the two groups are calculated. Different assumptions regarding anisotropic and inelastic scattering are investigated. The effects of backscattering from the moderator and fast fission in neighbouring fuel elements are pointed out. Formulas for the fast fission ratio and for the fast conversion ratio are derived. The calculated fast fission ratios are compared with experimental values. Curves are given for the fast fission factor in uranium metal and uranium oxide.

  1. A comparative life cycle assessment of marine power systems

    International Nuclear Information System (INIS)

    Ling-Chin, Janie; Roskilly, Anthony P.

    2016-01-01

    Highlights: • Correlation among resources, emissions, key components and processes was attained. • Environmental benefits of innovative power systems were verified. • New-build system showed a great advantage over retrofit and conventional systems. • Relative contribution of significant components remained or became more profound. • Influence of fuel consumption quantity over the estimates varied with impact types. - Abstract: Despite growing interest in advanced marine power systems, knowledge gaps existed as it was uncertain which configuration would be more environmentally friendly. Using a conventional system as a reference, the comparative life cycle assessment (LCA) study aimed to compare and verify the environmental benefits of advanced marine power systems i.e. retrofit and new-build systems which incorporated emerging technologies. To estimate the environmental impact attributable to each system, a bottom-up integrated system approach was applied, i.e. LCA models were developed for individual components using GaBi, optimised operational profiles and input data standardised from various sources. The LCA models were assessed using CML2001, ILCD and Eco-Indicator99 methodologies. The estimates for the advanced systems were compared to those of the reference system. The inventory analysis results showed that both retrofit and new-build systems consumed less fuels (8.28% and 29.7% respectively) and released less emissions (5.2–16.6% and 29.7–55.5% respectively) during operation whilst more resources were consumed during manufacture, dismantling and the end of life. For 14 impact categories relevant to global warming, acidification, eutrophication, photochemical ozone creation and PM/respiratory inorganic health issues, reduction in LCIA results was achieved by retrofit (2.7–6.6%) and new-build systems (35.7–50.7%). The LCIA results of the retrofit system increased in ecotoxicity (1–8%), resource depletion (1–2%) and fossil fuel depletion

  2. Fission level densities

    International Nuclear Information System (INIS)

    Maslov, V.M.

    1998-01-01

    Fission level densities (or fissioning nucleus level densities at fission saddle deformations) are required for statistical model calculations of actinide fission cross sections. Back-shifted Fermi-Gas Model, Constant Temperature Model and Generalized Superfluid Model (GSM) are widely used for the description of level densities at stable deformations. These models provide approximately identical level density description at excitations close to the neutron binding energy. It is at low excitation energies that they are discrepant, while this energy region is crucial for fission cross section calculations. A drawback of back-shifted Fermi gas model and traditional constant temperature model approaches is that it is difficult to include in a consistent way pair correlations, collective effects and shell effects. Pair, shell and collective properties of nucleus do not reduce just to the renormalization of level density parameter a, but influence the energy dependence of level densities. These effects turn out to be important because they seem to depend upon deformation of either equilibrium or saddle-point. These effects are easily introduced within GSM approach. Fission barriers are another key ingredients involved in the fission cross section calculations. Fission level density and barrier parameters are strongly interdependent. This is the reason for including fission barrier parameters along with the fission level densities in the Starter File. The recommended file is maslov.dat - fission barrier parameters. Recent version of actinide fission barrier data obtained in Obninsk (obninsk.dat) should only be considered as a guide for selection of initial parameters. These data are included in the Starter File, together with the fission barrier parameters recommended by CNDC (beijing.dat), for completeness. (author)

  3. Independent fission yields of Rb and Cs from thermal-neutron-induced fission of 239Pu

    International Nuclear Information System (INIS)

    Balestrini, S.J.; Forman, L.

    1975-01-01

    The relative independent fission yields of Rb and Cs from thermal-neutron-induced fission of 239 Pu have been measured on line using a mass spectrograph and thermalized neutrons from a burst reactor. Independent yields were derived by normalizing the measurements to products of chain yields and fractional independent yields, estimating the latter from measured cumulative yields of Kr and Xe. Comparing the independent yields with those from 238 U fission, the 239 Pu results show shifts in isotopic yield distribution toward lower mass for both Rb and Cs and also toward the production of more Cs and less Rb when 239 Pu is fissioned

  4. Comparative study of 99Mo/99mTc generators at base of synthesized gels starting from activation and fission 99Mo

    International Nuclear Information System (INIS)

    Lopez M, I.Z.; Monroy G, F.; Rivero G, T.; Rojas N, P.

    2007-01-01

    The 99m Tc is used for diagnostic and therapy. It is produced starting from 99 Mo, absorbed in chromatographic columns, loaded with alumina that absorb only 0.2% of 99 Mo with high specific activities of 99 Mo, obtained from the 235 U fission. Given these conditions and limitations, new preparation procedures of 99 Mo/ 99m Tc generators, its have been developed, using zirconium molybdates gels that incorporates until 30% of 99 Mo, conserve similar characteristics of quality and purity that the traditional generator. The radiochemical characteristics of the 99m Tc elution, depend strongly on the gel preparation conditions. In particular, the present work has by object to determine the influence of the 99 Mo used type, fission or activation product, during the gels synthesis, as well as the used air flow for the agitation in the gels preparation and its influence in the 99 Mo/ 99m Tc generators quality. When diminishing the flow of agitation air the efficiency it increases and in the radionuclide purity of the eluates and when using 99 Mo from fission for the gels production it increases in an important way the elutriation efficiency, the radiochemical and radionuclide purity of the 99m Tc eluates. (Author)

  5. Angular momenta of fission fragments in the {alpha}-accompanied fission of {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Jandel, M.; Kliman, J.; Krupa, L.; Morhac, M. [Slovak Academy of Sciences, Department of Nuclear Physics, Bratislava (Slovakia); Joint Institute for Nuclear Research, Flerov Laboratory for Nuclear Reactions, Dubna (Russian Federation); Hamilton, J.H.; Kormicki, J.; Ramayya, A.V.; Hwang, J.K.; Luo, Y.X.; Fong, D.; Gore, P. [Vanderbilt University, Department of Physics, Nashville, TN (United States); Ter-Akopian, G.M.; Oganessian, Yu.Ts.; Rodin, A.M.; Fomichev, A.S.; Popeko, G.S. [Joint Institute for Nuclear Research, Flerov Laboratory for Nuclear Reactions, Dubna (Russian Federation); Daniel, A.V. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Rasmussen, J.O.; Macchiavelli, A.O.; Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Donangelo, R.; Cole, J.D.

    2005-06-01

    For the first time, average angular momenta of the ternary fission fragments {sup 100,102}Zr, {sup 106}Mo, {sup 144,146}Ba and {sup 138,140,142}Xe from the {alpha}-accompanied fission of {sup 252}Cf were obtained from relative intensities of prompt {gamma}-ray transitions with the use of the statistical model calculation. Average values of the angular momenta were compared with the corresponding values for the same fission fragments from the binary fission of {sup 252}Cf. Results indicate the presence of a decreasing trend in the average values of angular momenta induced in ternary fission fragments compared to the same binary fission fragments. On the average, the total angular momentum extracted for ternary fission fragments is {proportional_to}1.4{Dirac_h} lower than in binary fission. Consequently, results indicate that the mechanism of the ternary {alpha}-particles emission may directly effect an induction of angular momenta of fission fragments, and possible scenarios of such mechanisms are discussed. Further, the dependence of the angular momenta of {sup 106}Mo and {sup 140}Xe on the number of emitted neutrons from correlated pairs of primary fragments was obtained also showing a decreasing dependence of average angular momenta with increasing number of emitted neutrons. Consequences are briefly discussed. (orig.)

  6. Fast fission phenomena

    International Nuclear Information System (INIS)

    Gregoire, Christian.

    1982-03-01

    Experimental studies of fast fission phenomena are presented. The paper is divided into three parts. In the first part, problems associated with fast fission processes are examined in terms of interaction potentials and a dynamic model is presented in which highly elastic collisions, the formation of compound nuclei and fast fission appear naturally. In the second part, a description is given of the experimental methods employed, the observations made and the preliminary interpretation of measurements suggesting the occurence of fast fission processes. In the third part, our dynamic model is incorporated in a general theory of the dissipative processes studied. This theory enables fluctuations associated with collective variables to be calculated. It is applied to highly inelastic collisions, to fast fission and to the fission dynamics of compound nuclei (for which a schematic representation is given). It is with these calculations that the main results of the second part can be interpreted [fr

  7. Consultancy to review and finalize the IAEA publication 'Compendium on the use of fusion/fission hybrids for the utilization and transmutation of actinides and long-lived fission products'. Working material

    International Nuclear Information System (INIS)

    2004-01-01

    In addition to the traditional fission reactor research, fusion R and D activities are becoming of interest also to nuclear fission power development. There is renewed interest in utilizing fusion neutrons, Heavy Liquid Metals, and molten salts for innovative systems (energy production and transmutation). Indeed, for nuclear power development to become sustainable as a long-term energy option, innovative fuel cycle and reactor technologies will have to be developed to solve the problems of resource utilization and long-lived radioactive waste management. In this context Member States clearly expressed the need for comparative assessments of various transmutation reactors. Both the fusion and fission communities are currently investigating the potential of innovative reactor and fuel cycle strategies that include a fusion/fission system. The attention is mainly focused on substantiating the potential advantages of such systems: utilization and transmutation of actinides and long-lived fission products, intrinsic safety features, enhanced proliferation resistance, and fuel breeding capabilities. An important aspect of the ongoing activities is the comparison with the accelerator driven subcritical system (spallation neutron source), which is the other main option for producing excess neutrons. Apart from comparative assessments, knowledge preservation is another subject of interest to the Member States: the goal, applied to fusion/fission systems, is to review the status of, and to produce a 'compendium' of past and present achievements in this area

  8. Fission product yields

    International Nuclear Information System (INIS)

    Valenta, V.; Hep, J.

    1978-01-01

    Data are summed up necessary for determining the yields of individual fission products from different fissionable nuclides. Fractional independent yields, cumulative and isobaric yields are presented here for the thermal fission of 235 U, 239 Pu, 241 Pu and for fast fission (approximately 1 MeV) of 235 U, 238 U, 239 Pu, 241 Pu; these values are included into the 5th version of the YIELDS library, supplementing the BIBFP library. A comparison is made of experimental data and possible improvements of calculational methods are suggested. (author)

  9. Fission neutron multiplicity calculations

    International Nuclear Information System (INIS)

    Maerten, H.; Ruben, A.; Seeliger, D.

    1991-01-01

    A model for calculating neutron multiplicities in nuclear fission is presented. It is based on the solution of the energy partition problem as function of mass asymmetry within a phenomenological approach including temperature-dependent microscopic energies. Nuclear structure effects on fragment de-excitation, which influence neutron multiplicities, are discussed. Temperature effects on microscopic energy play an important role in induced fission reactions. Calculated results are presented for various fission reactions induced by neutrons. Data cover the incident energy range 0-20 MeV, i.e. multiple chance fission is considered. (author). 28 refs, 13 figs

  10. Measurement of prompt fission gamma-ray spectra in fast neutron-induced fission

    International Nuclear Information System (INIS)

    Laborie, J.M.; Belier, G.; Taieb, J.

    2012-01-01

    Knowledge of prompt fission gamma-ray emission has been of major interest in reactor physics for a few years. Since very few experimental spectra were ever published until now, new measurements would be also valuable to improve our understanding of the fission process. An experimental method is currently being developed to measure the prompt fission gamma-ray spectrum from some tens keV up to 10 MeV at least. The mean multiplicity and total energy could be deduced. In this method, the gamma-rays are measured with a bismuth germanate (BGO) detector which has the advantage to present a high P/T ratio and a high efficiency compared to other gamma-ray detectors. The prompt fission neutrons are rejected by the time of flight technique between the BGO detector and a fission trigger given by a fission chamber or a scintillating active target. Energy and efficiency calibration of the BGO detector were carried out up to 10.76 MeV by means of the Al-27(p, gamma) reaction. First prompt fission gamma-ray spectrum measurements performed for the spontaneous fission of Cf-252 and for 1.7 and 15.6 MeV neutron-induced fission of U-238 at the CEA, DAM, DIF Van de Graaff accelerator, will be presented. (authors)

  11. Thermal Energetic Reactor with High Reproduction of Fission Materials

    Directory of Open Access Journals (Sweden)

    Vladimir M. Kotov

    2012-01-01

    On the base of thermal reactors with high fission materials reproduction world atomic power engineering development supplying higher power and requiring smaller speed of raw uranium mining, than in the variant with fast reactors, is possible.

  12. Fusion-fission hybrid studies in the United States

    International Nuclear Information System (INIS)

    Moir, R.W.; Lee, J.D.; Berwald, D.H.; Cheng, E.T.; Delene, J.G.; Jassby, D.L.

    1986-01-01

    Systems and conceptual design studies have been carried out on the following three hybrid types: (1) The fission-suppressed hybrid, which maximizes fissile material produced (Pu or 233 U) per unit of total nuclear power by suppressing the fission process and multiplying neutrons by (n,2n) reactions in materials like beryllium. (2) The fast-fission hybrid, which maximizes fissile material produced per unit of fusion power by maximizing fission of 238 U (Pu is produced) in which twice the fissile atoms per unit of fusion power (but only a third per unit of nuclear power) are made. (3) The power hybrid, which amplifies power in the blanket for power production but does not produce fuel to sell. All three types must sell electrical power to be economical

  13. What can be learnt from the channel analysis of the 232Th neutron fission cross section

    International Nuclear Information System (INIS)

    Abou Yehia, H.; Jary, J.; Trochon, J.; Boldeman, J.W.; Musgrove, A.R. de L.

    1979-10-01

    Channel analyses of the neutron fission cross section of 232 Th have been made in two laboratories. The calculated fission cross sections and fission fragment anisotropies are compared with the experimental data. Despite some differences in the methods used, the conclusions on the physical aspects of the fission process are very similar

  14. Energy from nuclear fission an introduction

    CERN Document Server

    De Sanctis, Enzo; Ripani, Marco

    2016-01-01

    This book provides an overview on nuclear physics and energy production from nuclear fission. It serves as a readable and reliable source of information for anyone who wants to have a well-balanced opinion about exploitation of nuclear fission in power plants. The text is divided into two parts; the first covers the basics of nuclear forces and properties of nuclei, nuclear collisions, nuclear stability, radioactivity, and provides a detailed discussion of nuclear fission and relevant topics in its application to energy production. The second part covers the basic technical aspects of nuclear fission reactors, nuclear fuel cycle and resources, safety, safeguards, and radioactive waste management. The book also contains a discussion of the biological effects of nuclear radiation and of radiation protection, and a summary of the ten most relevant nuclear accidents. The book is suitable for undergraduates in physics, nuclear engineering and other science subjects. However, the mathematics is kept at a level that...

  15. Comparative study of 99Mo/99mTc generators at base of synthesized gels starting from 99Mo of activation and of fission

    International Nuclear Information System (INIS)

    Lopez M, I.Z.; Monroy G, F.; Rivero G, T.; Rojas N, P.

    2007-01-01

    At the present time the more used and diffused radionuclide in nuclear medicine it is the Technetium 99 metastable ( 99 mTc) it is used for diagnostic and therapy. It is produced starting from molybdenum 99 ( 99 Mo), which is absorbed in chromatographic columns, loaded with alumina that absorb only 0.2% of 99 Mo situation that forces to use high specific activities of 99 Mo that it is obtained starting from the fission of the 235 U. Given these conditions and limitations, new preparation procedures of 99 Mo/ 99m Tc generators, of low or medium specific activity, its have been developed, using gels of zirconium molybdates that incorporates until 30% in weight of 99 Mo in the gel, and also conserve similar characteristics of quality and purity that those obtained by the traditional generator; reducing by this way the cost of production of the 99m Tc, when using 99 Mo of low specific activity, in the preparation of 99 Mo/ 99m Tc generators. The radiochemical characteristics of the elution of 99m Tc, depends strongly on the gel preparation conditions. In particular, the present work has for object to determine the influence of the used type of 99 Mo, fission or activation product, during the gels synthesis, as well as the used air flow for the agitation in the gels preparation and its influence in the quality of the 99 Mo/ 99m Tc generators. When diminishing the agitation air flow the efficiency it increases and in the radionuclide purity of the eluates and when using 99 Mo of fission for the gels production it increases in an important way the elution efficiency, the radiochemical purity and radionuclide of the eluates of 99m Tc. (Author)

  16. Measurements of fission cross-sections. Chapter 4

    International Nuclear Information System (INIS)

    James, G.D.

    1981-01-01

    The steps involved in the measurement of fission cross sections are summarized and the range of techniques available are considered. Methods of fission detection are described with particular emphasis on the neutron energy dependent properties of the fission process and the details of fragment energy loss which can lead to energy-dependent changes in detector efficiency. Selected examples of fission cross-section measurements are presented and methods of data reduction, storage, analysis and evaluation, are examined. Finally requested accuracies for fission cross section data are compared to estimated available accuracies. (U.K.)

  17. The nuclear fission

    International Nuclear Information System (INIS)

    Fiorentino, J.

    1983-01-01

    The nuclear fission process considering initially the formation of compound nucleus and finishing with radioactive decay of fission products is studied. The process is divided in three parts which consist of the events associated to the nucleus of intermediate transitional state, the scission configuration, and the phenomenum of post scission. (M.C.K.) [pt

  18. Fission gas detection system

    International Nuclear Information System (INIS)

    Colburn, R.P.

    1984-01-01

    A device for collecting fission gas released by failed fuel rods which device uses a filter adapted to pass coolant but to block passage of fission gas bubbles due to the surface tension of the bubbles. The coolant may be liquid metal. (author)

  19. Muon-induced fission

    International Nuclear Information System (INIS)

    Polikanov, S.

    1980-01-01

    A review of recent experimental results on negative-muon-induced fission, both of 238 U and 232 Th, is given. Some conclusions drawn by the author are concerned with muonic atoms of fission fragments and muonic atoms of the shape isomer of 238 U. (author)

  20. Relativistic Coulomb Fission

    Science.gov (United States)

    Norbury, John W.

    1992-01-01

    Nuclear fission reactions induced by the electromagnetic field of relativistic nuclei are studied for energies relevant to present and future relativistic heavy ion accelerators. Cross sections are calculated for U-238 and Pu-239 fission induced by C-12, Si-28, Au-197, and U-238 projectiles. It is found that some of the cross sections can exceed 10 b.

  1. Advanced nuclear fuel production by using fission-fusion hybrid reactor

    International Nuclear Information System (INIS)

    Al-Kusayer, T.A.; Sahin, S.; Abdulraoof, M.

    1993-01-01

    Efforts are made at the College of Engineering, King Saud University, Riyadh to lay out the main structure of a prototype experimental fusion and fusion-fission (hybrid) reactor blanket in cylindrical geometry. The geometry is consistent with most of the current fusion and hybrid reactor design concepts in respect of the neutronic considerations. Characteristics of the fusion chamber, fusion neutrons and the blanket are provided. The studies have further shown that 1 GWe fission-fusion reactor can produce up to 957 kg/year which is enough to fuel five light water reactors of comparable power. Fuel production can be increased further. 29 refs

  2. Modeling fission gas release in high burnup ThO2-UO2 fuel

    International Nuclear Information System (INIS)

    Long, Y.; Yuan, Y.; Pilat, E.E.; Rim, C.S.; Kazimi, M.S.

    2001-01-01

    A preliminary fission gas release model to predict the performance of thoria fuel using the FRAPCON-3 computer code package has been formulated. The following modeling changes have been made in the code: - Radial power/burnup distribution; - Thermal conductivity and thermal expansion; - Rim porosity and fuel density; - Diffusion coefficient of fission gas in ThO 2 -UO 2 fuel and low temperature fission gas release model. Due to its lower epithermal resonance absorption, thoria fuel experiences a much flatter distribution of radial fissile products and radial power distribution during operation as compared to uranian fuel. The rim effect and its consequences in thoria fuel, therefore, are expected to occur only at relatively high burnup levels. The enhanced conductivity is evident for ThO 2 , but for a mixture the thermal conductivity enhancement is small. The lower thermal fuel expansion tends to negate these small advantages. With the modifications above, the new version of FRAPCON-3 matched the measured fission gas release data reasonably well using the ANS 5.4 fission gas release model. (authors)

  3. Study on fission blanket fuel cycling of a fusion-fission hybrid energy generation system

    International Nuclear Information System (INIS)

    Zhou, Z.; Yang, Y.; Xu, H.

    2011-01-01

    This paper presents a preliminary study on neutron physics characteristics of a light water cooled fission blanket for a new type subcritical fusion-fission hybrid reactor aiming at electric power generation with low technical limits of fission fuel. The major objective is to study the fission fuel cycling performance in the blanket, which may possess significant impacts on the feasibility of the new concept of fusion-fission hybrid reactor with a high energy gain (M) and tritium breeding ratio (TBR). The COUPLE2 code developed by the Institute of Nuclear and New Energy Technology of Tsinghua University is employed to simulate the neutronic behaviour in the blanket. COUPLE2 combines the particle transport code MCNPX with the fuel depletion code ORIGEN2. The code calculation results show that soft neutron spectrum can yield M > 20 while maintaining TBR >1.15 and the conversion ratio of fissile materials CR > 1 in a reasonably long refuelling cycle (>five years). The preliminary results also indicate that it is rather promising to design a high-performance light water cooled fission blanket of fusion-fission hybrid reactor for electric power generation by directly loading natural or depleted uranium if an ITER-scale tokamak fusion neutron source is achievable.

  4. Comparative modeling for power generating systems with interaction phenomena

    International Nuclear Information System (INIS)

    Kim, Seong Ho; Kim, Tae Woon

    2007-01-01

    From a conflicting viewpoint, comprehensive assessment of various national power systems can be treated as a multicriteria decision-making (MCDM) problem. In reality, there are interaction phenomena among the decision elements. The main objective of this work is to propose a comprehensive framework to determinate the priority of appropriate national power sources involving various degrees of interaction among the decision elements (e.g., decision goal, decision criteria, and decision alternatives) such as inner dependence, outer dependence, and feedback effect. In the context of a generic hierarchical network (or hiernet) structure instead of one-way directional tree structure, the impact of the interaction phenomena on the grade of priority is investigated using a supermatrix technique or an analytic network process (ANP) method. Moreover, the three types of attitudes towards nuclear power system of the multiple actors are incorporated into the network structure to figure out the effect of characteristics of power systems. An illustrative example of the generic hiernet structure is demonstrated in comparison to the specific hierarchy structure without any interaction among the decision elements. The proposed framework can be applied to select the appropriate power systems, to understand the effect of its underlying decision structures, and to include risk attitudes towards a certain alternative. (author)

  5. Study of hypernuclei fission

    International Nuclear Information System (INIS)

    Malek, F.

    1990-01-01

    This work is about PS177 experience made on LEAR machine at CERN in 1988. The annihilation reaction of anti protons on a target of Bismuth or Uranium is studied. Lambda particles are produced by this reaction, in the nucleus in 2% of cases 7.1 10 -3 hypernuclei by stopped antiproton in the target are produced. The prompt hypernucleus fission probability of uranium is 75% and that of Bismuth 10%. The mass distribution of fission fragments is symmetrical ((≡ the excitation energy of the nucleus is very high). If the nucleus hasn't fissioned, the non-mesonic lambda decay, gives it an energy of 100 MeV, what allows to fission later. This fission is delayed because the hypernucleus lifetime is 1.3 +0.25 -0.21 10 -10 sec for Bismuth [fr

  6. Benefits and hazards of nuclear power

    International Nuclear Information System (INIS)

    Barnert, H.; Borsch, P.; Feldmann, A.; Merz, E.; Muench, E.; Oesterwind, D.; Voss, A.; Wolters, J.

    1979-09-01

    Compilation of a seminar at the KFA Juelich on topical problems of nuclear power. Subjects: Energy demand, its expected development and possibilities of coverage; physical fundamentals and technical realisation of power generation by nuclear fission; fuel cycle problems and solutions; effects of radioactive radiation; safety of nuclear power plants and the nuclear hazard as compared with other hazards. (orig./RW) [de

  7. Fission 2009 4. International Workshop on Nuclear Fission and Fission Product Spectroscopy - Compilation of slides

    International Nuclear Information System (INIS)

    2009-01-01

    This conference is dedicated to the last achievements in experimental and theoretical aspects of the nuclear fission process. The topics include: mass, charge and energy distribution, dynamical aspect of the fission process, nuclear data evaluation, quasi-fission and fission lifetime in super heavy elements, fission fragment spectroscopy, cross-section and fission barrier, and neutron and gamma emission. This document gathers the program of the conference and the slides of the presentations

  8. Comparative evaluation of nuclear power in developing countries

    International Nuclear Information System (INIS)

    Obermair, G.M.

    1990-01-01

    Even in those developing countries where nuclear power is technically feasible and competitive against the alternatives, most other factors weigh heavily against the nuclear path for the next decades. This does not mean that nuclear power should be completely ruled out in the longer run. At the moment several problems of nuclear power, in particular its follow-up effects and costs, are not really solved. The results of present efforts toward their solution can probably only be judged in the 1990s. It is not now clear whether the total outcome of nuclear energy is positive, even in the industrialized countries. Any country with an evenly developed technical infrastructure and a sufficiently broad basis of intellectual and technical skills will be able to acquire the specialized nuclear knowhow within a few years. For the meantime,in the opinion of the author, national and international efforts should establish technical school and faculties, study groups should be set up that analyse the energy situation in the individual countries in depth and watch international developments in the nuclear sector. A thorough knowledge of the unresolved problems will prevent their being ignored in the intellectual fascination and political challenge of nuclear power. (author). 11 refs., 3 tabs

  9. Fission rates measured using high-energy gamma-rays from short half-life fission products in fresh and spent nuclear fuel

    International Nuclear Information System (INIS)

    Kroehnert, H.

    2011-02-01

    -irradiated burnt UO 2 fuel samples with burn-ups of about 36 and 46 GWd/t. Based on experiments carried out with these fuel samples in a reference test lattice of the PROTEUS reactor, fresh-to-burnt-fuel fission rate ratios could be determined. The 1σ uncertainties on the derived fission rate ratios are 1.7 to 3.4% and are mainly due to the statistical uncertainties. Calculated values of the fission rate ratios, as obtained using the Monte Carlo code MCNPX, have been shown to agree with the experimental results within these uncertainties. In deriving fresh-to-burnt-fuel fission rate ratios, 142 La and 138 Cs have emerged as the preferred fission products. Their fission yields for the main fissile isotopes ( 235 U, 239 Pu and 241 Pu) are similar, which makes them relatively insensitive to the exact composition of the burnt fuel. Finally, a measurement station for the future LIFE(at)PROTEUS experiments has been proposed and evaluated, along with a detailed formulation of recommendations for optimised irradiation and measurement strategies. The estimated accuracy for the foreseen measurements of fission rate ratios between fresh and highly burnt fuel pins is 1 to 2%. The contribution of nuclear-data related uncertainties have been pointed out as possibly representing the main constraint on the achievable accuracy in future experiments. In brief, the present research work has established a novel experimental technique for measuring and comparing fission rates in fresh and highly burnt fuels in a zero-power research reactor such as PROTEUS. Moreover, possibilities have been presented for the further optimisation needed for a future, routine application of the technique. (author)

  10. Fission rates measured using high-energy gamma-rays from short half-life fission products in fresh and spent nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Kroehnert, H.

    2011-02-15

    measured and quantitatively evaluated for re-irradiated burnt UO{sub 2} fuel samples with burn-ups of about 36 and 46 GWd/t. Based on experiments carried out with these fuel samples in a reference test lattice of the PROTEUS reactor, fresh-to-burnt-fuel fission rate ratios could be determined. The 1σ uncertainties on the derived fission rate ratios are 1.7 to 3.4% and are mainly due to the statistical uncertainties. Calculated values of the fission rate ratios, as obtained using the Monte Carlo code MCNPX, have been shown to agree with the experimental results within these uncertainties. In deriving fresh-to-burnt-fuel fission rate ratios, {sup 142}La and {sup 138}Cs have emerged as the preferred fission products. Their fission yields for the main fissile isotopes ( {sup 235}U, {sup 239}Pu and {sup 241}Pu) are similar, which makes them relatively insensitive to the exact composition of the burnt fuel. Finally, a measurement station for the future LIFE(at)PROTEUS experiments has been proposed and evaluated, along with a detailed formulation of recommendations for optimised irradiation and measurement strategies. The estimated accuracy for the foreseen measurements of fission rate ratios between fresh and highly burnt fuel pins is 1 to 2%. The contribution of nuclear-data related uncertainties have been pointed out as possibly representing the main constraint on the achievable accuracy in future experiments. In brief, the present research work has established a novel experimental technique for measuring and comparing fission rates in fresh and highly burnt fuels in a zero-power research reactor such as PROTEUS. Moreover, possibilities have been presented for the further optimisation needed for a future, routine application of the technique. (author)

  11. Modeling of fuel performance and fission product release behavior during HTTR normal operation. A comparative study of the FZJ and JAERI modeling approach

    International Nuclear Information System (INIS)

    Verfondern, Karl; Sumita, Junya; Ueta, Shohei; Sawa, Kazuhiro

    2001-03-01

    For the prediction of fuel performance and fission product release behavior in the High Temperature Engineering Test Reactor, HTTR of the Japan Atomic Energy Research Institute(JAERI), during its normal operation, calculation tools were applied as have been used at the Research Center Juelich (FZJ) in safety analyses for pebble-bed HTGR designs. Calculations were made assuming the HTTR operation with a nominal operation time of 660 efpd including a 110 efpd period with elevated fuel temperatures. Fuel performance calculations by the PANAMA code with given fuel temperature distribution in the core have shown that the additional failure level of about 5x10 -6 is expected which is about twice as much as the as-fabricated through-coatings failure level. Under the extreme safety design conditions, the predicted particle failure fraction in the core increases to about 1x10 -3 in maximum. The diffusive release of metallic fission products from the fuel primarily occurs in the core layer with the maximum fuel temperature (layer 3) whereas there is hardly any contribution from layer 1 except for the recoil fraction. Silver most easily escapes the fuel; the predicted release fractions from the fuel compacts are 10% (expected) and 50% (safety design). The figures for strontium (expected: 1.5x10 -3 ), safety design: 3.1x10 -2 ) and cesium (5.6x10 -4 , 2.9x10 -2 ) reveal as well a significant fraction to originate already from intact particles. Comparison with the calculation based on JAERI's diffusion model for cesium shows a good agreement for the release behavior from the particles. The differences in the results can be explained mainly by the different diffusion coefficients applied. The release into the coolant can not modelled because of the influence of the gap between compact and graphite sleeve lowering the release by a factor of 3 to 10. For the prediction of performance and fission product release behavior of advanced ZrC TRISO particles, more experimental work is

  12. Stopping power for heavy ions in gases: a comparative study

    International Nuclear Information System (INIS)

    Diwan, P.K.; Singh, Lakhwant; Singh, Gurinder; Shyam Kumar

    1999-01-01

    The accurate knowledge of stopping power for heavy ions in gases is of paramount importance in nuclear reaction studies for the identification of reaction products involving ΔE-E telescope detectors. In the present work, it has been calculated the stopping power values for different heavy ions, such as Ne, Ar, Cu, Kr and Ag in various gas absorbers like H 2 , He, N 2 , Ne, Ar, Kr and Xe in the energy domain ∼ 2.5-6 MeV/n using the SRIM-98 code recently developed by Ziegler and the formulations of Benton and Henke, Hubert et al, Mukherjee and Nayak and Northcliffe and Schilling. This study has been undertaken in order to establish the validity of various semiempirical formulations for gas targets

  13. Fission neutron spectra measurements at LANSCE - Status and plans

    International Nuclear Information System (INIS)

    Haight, R. C.; Noda, S.; Nelson, R. O.; O'Donnell, J. M.; Devlin, M.; Chatillon, A.; Granier, T.; Taiebb, J.; Laurent, B.; Belier, G.; Becker, J. A.; Wu, C. Y.

    2010-01-01

    A program to measure fission neutron spectra from neutron-induced fission of actinides is underway at the Los Alamos Neutron Science Center (LANSCE) in a collaboration among the CEA laboratory at Bruyeres-le-Chatel, Lawrence Livermore National Laboratory and Los Alamos National Laboratory. The spallation source of fast neutrons at LANSCE is used to provide incident neutron energies from less than 1 MeV to 100 MeV or higher. The fission events take place in a gas-ionization fission chamber, and the time of flight from the neutron source to that chamber gives the energy of the incident neutron. Outgoing neutrons are detected by an array of organic liquid scintillator neutron detectors, and their energies are deduced from the time of flight from the fission chamber to the neutron detector. Measurements have been made of the fission neutrons from fission of 235 U, 238 U, 237 Np and 239 Pu. The range of outgoing energies measured so far is from 0.7 MeV to approximately 8 MeV. These partial spectra and average fission neutron energies are compared with evaluated data and with models of fission neutron emission. Results to date are summarized in this presentation. Future plans are to make significant improvements in the fission chambers, neutron detectors, signal processing, data acquisition and the experimental environment to provide high fidelity data including measurements of fission neutrons below 0.7 MeV and improvements in the data above 8 MeV. (authors)

  14. Comparing costs of power and heat production by prospective and present sources

    International Nuclear Information System (INIS)

    Novak, S.

    1979-01-01

    Capital and running costs are compared of power and heat production from different sources. The lowest capital costs were found for coal-fired power plants followed by light water reactor power plants. The capital costs of other types of power plants, such as wind, geothermal, solar, thermonuclear power plants are significantly higher. The estimated specific cost for electric power production in 1985 for a nuclear power plant is lower than for a fossil-fuel power plant. It is estimated that in 1985 coal will be the cheapest heat source. (Ha)

  15. Fusion-Fission Hybrid for Fissile Fuel Production without Processing

    Energy Technology Data Exchange (ETDEWEB)

    Fratoni, M; Moir, R W; Kramer, K J; Latkowski, J F; Meier, W R; Powers, J J

    2012-01-02

    Two scenarios are typically envisioned for thorium fuel cycles: 'open' cycles based on irradiation of {sup 232}Th and fission of {sup 233}U in situ without reprocessing or 'closed' cycles based on irradiation of {sup 232}Th followed by reprocessing, and recycling of {sup 233}U either in situ or in critical fission reactors. This study evaluates a third option based on the possibility of breeding fissile material in a fusion-fission hybrid reactor and burning the same fuel in a critical reactor without any reprocessing or reconditioning. This fuel cycle requires the hybrid and the critical reactor to use the same fuel form. TRISO particles embedded in carbon pebbles were selected as the preferred form of fuel and an inertial laser fusion system featuring a subcritical blanket was combined with critical pebble bed reactors, either gas-cooled or liquid-salt-cooled. The hybrid reactor was modeled based on the earlier, hybrid version of the LLNL Laser Inertial Fusion Energy (LIFE1) system, whereas the critical reactors were modeled according to the Pebble Bed Modular Reactor (PBMR) and the Pebble Bed Advanced High Temperature Reactor (PB-AHTR) design. An extensive neutronic analysis was carried out for both the hybrid and the fission reactors in order to track the fuel composition at each stage of the fuel cycle and ultimately determine the plant support ratio, which has been defined as the ratio between the thermal power generated in fission reactors and the fusion power required to breed the fissile fuel burnt in these fission reactors. It was found that the maximum attainable plant support ratio for a thorium fuel cycle that employs neither enrichment nor reprocessing is about 2. This requires tuning the neutron energy towards high energy for breeding and towards thermal energy for burning. A high fuel loading in the pebbles allows a faster spectrum in the hybrid blanket; mixing dummy carbon pebbles with fuel pebbles enables a softer spectrum in

  16. Risk-based Comparative Study of Fluid Power Pitch Concepts

    DEFF Research Database (Denmark)

    Liniger, Jesper; Pedersen, Henrik Clemmensen; N. Soltani, Mohsen

    2017-01-01

    Proper functioning of the pitch system is essential to both normal operation and safety critical shut down of modern multi megawatt wind turbines. Several studies on field failure rates for such turbines show that pitch systems are a major contributor to failures which entails an increased risk....... Thus, more reliable and safe concepts are needed. A review of patents and patent applications covering fluid power pitch concepts, reveals that many propose closed-type hydraulic systems. This paper proposes a closed-type concept with a bootstrap reservoir. In contrary to a conventional system where...

  17. Improving Power System Stability Using Transfer Function: A Comparative Analysis

    Directory of Open Access Journals (Sweden)

    G. Shahgholian

    2017-10-01

    Full Text Available In this paper, a small-signal dynamic model of a single-machine infinite-bus (SMIB power system that includes IEEE type-ST1 excitation system and PSS based on transfer fu¬n¬c¬¬tion structure is presented. The changes in the operating co¬n¬dition of a power system on dynamic performance have been exa¬m¬ined. The dynamic performance of the closed-loop system is ana¬lyzed base on its eigenvalues. The effectiveness of the par¬a¬m¬e¬t¬ers changes on dynamic stability is verified by simulation res¬u¬l¬ts. Three types of PSS have been considered for analysis: (a the derivative PSS, (b the lead-lag PSS or conventional PSS, and (c the proportional-integral-derivative PSS. The objective fu¬nc¬t¬i¬o¬n is formulated to increase the dam¬¬ping ratio of the electromechanical mode eigenvalues. Simu¬la¬tion results show that the PID-PSS performs better for less ov¬e¬r¬shoot and less settling time comp¬ared with the CPSS and DPSS un¬der different load ope¬ration and the significant system pa¬r¬am¬eter variation conditions.

  18. Nuclear Dissipation from Fission Time

    International Nuclear Information System (INIS)

    Gontchar, I.; Morjean, M.; Basnary, S.

    2000-01-01

    Fission times, pre-scission neutron multiplicities and GDR pre-scission γ-ray multiplicities measured for uranium or thorium nuclei formed with temperatures T ∼ 1.8 MeV have been compared with calculations performed with CDSM2, a two-dimensional dynamical model combined with a statistical one. Among the three experimental approaches considered, fission times give access to the most precise pieces of information on nuclear dissipation at high excitation energy. For the temperature range under consideration, an agreement between the model and data is achieved if one-body dissipation is used with a strength factor k red ∼ 0.45 ± 0.10 applied to the wall term for the mononuclear configuration. (authors)

  19. International conference on comparative assessments of solar power technologies

    International Nuclear Information System (INIS)

    Roy, A.

    1994-02-01

    Many regions in the world which lack fossil fuel resources but possess ample sunshine seek to identify near-term solar technologies capable of gradually replacing their fuel imports in cost-effective fashion. The conference addresses the following topics: technical and economical studies specifying their underlying basic assumption, methods and rules for evaluation in order to enable meaningful comparison between different technologies and systems. Detailed delineation of numerical and graphical representations, critical analysis and comparison between simulations, and test validity. Generalized performance indicators for systems and subsystems, problems of measuring and evaluating physical parameters, of terminology and conceptual tools for comparative evaluations. Advances in research development, engineering and field performance, including implications pertaining to comparative assessments and definitions of criteria and standards helpful to comparative evaluation. Assessments of the full (and hidden) cost of fossil energies as compared to solar, including environmental costs. Cost/benefit studies for remote versus centralized systems. (ed.)

  20. Fission barriers of superheavy nuclei

    International Nuclear Information System (INIS)

    Burvenich, T.

    2001-01-01

    Full text: Self consistent microscopic mean-field models are powerful tools for the description of nuclear structure phenomena in the region of known elements, where they have reached a good quality. Especially the Skyrme-Hartree-Fock (SHF) method and the Relativistic Mean-Field (RMF) model will be considered in the discussion of the properties of these models. When it comes to extrapolation to the region of superheavy elements, though there is agreement concerning the global trends, these model exhibit significant differences in their predictions concerning fission barrier heights and structures. (Author)

  1. Fission in a Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Younes, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-26

    A three-year theory project was undertaken to study the fission process in extreme astrophysical environments, such as the crust of neutron stars. In the first part of the project, the effect of electron screening on the fission process was explored using a microscopic approach. For the first time, these calculations were carried out to the breaking point of the nucleus. In the second part of the project, the population of the fissioning nucleus was calculated within the same microscopic framework. These types of calculations are extremely computer-intensive and have seldom been applied to heavy deformed nuclei, such as fissioning actinides. The results, tools and methodologies produced in this work will be of interest to both the basic-science and nuclear-data communities.

  2. Investigation of delayed fission gas release

    International Nuclear Information System (INIS)

    Cayet, Nicolas

    1996-05-01

    The study of the fission gas release process in the high burnup rig IFA-562 has revealed a particular fuel behaviour: a delay in the fission gas release process. It appeared that an important release of gas was measured by the pressure transducers once the power had decreased, whereas, during steady-state operation, the pressure did not increase very much. After examinations, the gap size has been concluded to be the main parameter involving this delay. However the burnup could have been a potential factor, its role is mainly to close the gap by swelling. The observations of low burnup rods have shown the same delayed fission gas release, the gap being small by design and closed essentially by thermal expansion. The study of the kinetics has demonstrated the time-independency of the phenomenon. Thus the proposed mechanism driving this delayed fission gas release would involve three consecutives stages. During steady-state, the gas is released into the interlinkage network of grain boundary bubbles and cracks. Due to the closed gap, the gas is trapped in some void volumes, unable to escape the pellet. During power reduction, the gap and some old/new cracks open, immediately providing a path for the gas to the pressure transducers and explaining this delay in the fission gas release. (author)

  3. Nuclear-powered Hysat spacecraft: comparative design study

    International Nuclear Information System (INIS)

    Raab, B.

    1975-08-01

    The study shows that the all-nuclear spacecraft can have a substantial weight advantage over a hybrid (nuclear/solar) or all-solar spacecraft, owing to a further reduction in power requirement, and to the elimination of such equipment as the sensor gimbal and rotating joint assemblies. Because the need for a sun-oriented section is eliminated, the all-nuclear spacecraft can be designed as a monolithic structure, with the sensor and other payload firmly secured in a fixed position on the structure. This enhances attitude stability while minimizing structural weight and eliminating the need for flexible fluid lines. Sensor motion can be produced, varied, and controlled within the limits specified by the study contractors by moving the entire spacecraft in the prescribed pattern. A simple attitude control system using available hardware suffices to meet all requirements

  4. Microscopic Theory of Fission

    International Nuclear Information System (INIS)

    Younes, W; Gogny, D

    2008-01-01

    In recent years, the microscopic method has been applied to the notoriously difficult problem of nuclear fission with unprecedented success. In this paper, we discuss some of the achievements and promise of the microscopic method, as embodied in the Hartree-Fock method using the Gogny finite-range effective interaction, and beyond-mean-field extensions to the theory. The nascent program to describe induced fission observables using this approach at the Lawrence Livermore National Laboratory is presented

  5. A Preliminary Study on Time Projection Chamber Simulation for Fission Cross Section Measurements with Geant4

    International Nuclear Information System (INIS)

    Kim, Jong Woon; Lee, Youngouk; Kim, Jae Cheon

    2014-01-01

    We present the details of the TPC simulation with Geant4 and show the results. TPC can provide more information than a fission chamber in that it is possible to distinguish different particle types. Simulations are conducted for uranium and plutonium targets with 20MeV neutrons. The simulation results are compared with the reference and show reasonable results. This is the first phase of study for realizing a TPC in the NFS at RAON, and we have more work to do, such as applying an electric field, signal processing in the simulation, and manufacturing of a TPC. The standard in fission cross section measurement is a fission chamber. It is basically just two parallel plates separated by a few centimeters of gas. A power supply connected to the plates sets up a moderate electric field. The target is deposited onto one of the plates. When fission occurs, the fragments ionize the gas, and the electric field causes the produced electrons to drift to the opposite plate, which records the total energy deposited in the chamber. A Time Projection Chamber (TPC) is a gas ionization detector similar to a fission chamber. However, it can measure the charged particle trajectories in the active volume in three dimensions by adding several readouts on the pad plane (fission chamber has only one readout one a pad plane). The specific ionization for each particle track enables the TPC to distinguish different particle types. A TPC will be used for fission cross section measurements in the Neutron Science Facility (NSF) at RAON. As a preliminary study, we present details of TPC simulation with Geant4 and discuss the results

  6. Accessing powerful knowledge: a comparative study of two first year ...

    African Journals Online (AJOL)

    This paper presents a case study of two first year sociology courses run at an elite South African university in order to speak to student perspectives on the sociology curriculum. The paper provides a comparative analysis of the academic experiences of extended degree (ED) students registered on two first year courses, ...

  7. Determination of the neutron-induced fission cross section of 242Pu

    International Nuclear Information System (INIS)

    Koegler, Toni Joerg

    2016-01-01

    Neutron induced fission cross sections of actinides like the Pu-isotopes are of relevance for the development of nuclear transmutation technologies. For 242 Pu, current uncertainties are of around 21%. Sensitivity studies show that the total uncertainty has to be reduced to below 5% to allow for reliable neutron physics simulations. This challenging task was performed at the neutron time-of-flight facility of the new German National Center for High Power Radiation Sources at HZDR, Dresden. Within the TRAKULA project, thin, large and homogeneous deposits of 235 U and 242 Pu have been produced successfully. Using two consecutively placed fission chambers allowed the determination of the neutron induced fission cross section of 242 Pu relative to 235 U. The areal density of the Plutonium targets was calculated using the measured spontaneous fission rate. Experimental results of the fast neutron induced fission of 242 Pu acquired at nELBE will be presented and compared to recent experiments and evaluated data. Corrections addressing the neutron scattering are discussed by using results of different neutron transport simulations (Geant 4, MCNP 6 and FLUKA).

  8. Study of the number of neutrons produced by fission of {sup 239}Pu; Etude du nombre de neutrons produits par la fission de {sup 239}Pu

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    Study of the number of neutrons produced by fission of {sup 239}Pu. The counting by coincidence of fissions and neutrons produced by these fissions allows the study of the variation of the mean number of neutrons emitted by {nu} fission. In the first chapter, it studied the variation of the mean number of neutrons emitted by {sup 239}Pu fission with the energy of the incident neutron. A description of the experiment is given: a spectrometer with a crystal of sodium chloride or beryllium (mounted on a goniometer) is used, a fission chamber containing 10 mg of {sup 239}Pu and the neutron detection system constituted of BF{sub 3} counters which are enriched in {sup 10}B. In the second part, the counting by coincidence of fissions and neutrons produced by the same fission and received by two different groups of counters allow the determination of a relationship between the root mean square and the average of neutron number produced by fission. The variation of the mean number of neutrons emitted by fission of {sup 239}Pu is studied when we change from a thermal spectra of neutrons to a fission spectra of incident neutrons. Finally, when separating in two different part the fission chamber, it is possible to measure the mean number of neutrons emitted from fission of two different sources. It compared the mean number of neutrons emitted by fission of {sup 239}Pu and {sup 233}U. (M.P.)

  9. Modelisation of the fission cross section

    International Nuclear Information System (INIS)

    Morariu, Claudia

    2013-03-01

    The neutron cross sections of four nuclear systems (n+ 235 U, n+ 233 U, n+ 241 Am and n+ 237 Np) are studied in the present document. The target nuclei of the first case, like 235 U and 239 Pu, have a large fission cross section after the absorption of thermal neutrons. These nuclei are called 'fissile' nuclei. The other type of nuclei, like 237 Np and 241 Am, fission mostly with fast neutrons, which exceed the fission threshold energy. These types of nuclei are called 'fertile'. The compound nuclei of the fertile nuclei have a binding energy higher than the fission barrier, while for the fissile nuclei the binding energy is lower than the fission barrier. In this work, the neutron induced cross sections for both types of nuclei are evaluated in the fast energy range. The total, reaction and shape-elastic cross sections are calculated by the coupled channel method of the optical model code ECIS, while the compound nucleus mechanism are treated by the statistical models implemented in the codes STATIS, GNASH and TALYS. The STATIS code includes a refined model of the fission process. Results from the theoretical calculations are compared with data retrieved from the experimental data base EXFOR. (author) [fr

  10. Study on the calculation method of source term from fission products

    International Nuclear Information System (INIS)

    Zhou Jing; Gong Quan; Qiu Haifeng

    2014-01-01

    As a major part of radioactive nuclides, fission products play an important role in nuclear power plant design. The paper analyzes the calculation model of core activity inventory, the model of fission products releasing from the pellets to RCS, the balance model of fission products in RCS, and then proves them by calculation of the typical pressurized water reactor. The model is proved applicable for calculating fission products of pressurized water reactors. (authors)

  11. Modeling of in-vessel fission product release including fuel morphology effects for severe accident analyses

    International Nuclear Information System (INIS)

    Suh, K.Y.

    1989-10-01

    A new in-vessel fission product release model has been developed and implemented to perform best-estimate calculations of realistic source terms including fuel morphology effects. The proposed bulk mass transfer correlation determines the product of fission product release and equiaxed grain size as a function of the inverse fuel temperature. The model accounts for the fuel-cladding interaction over the temperature range between 770 K and 3000 K in the steam environment. A separate driver has been developed for the in-vessel thermal hydraulic and fission product behavior models that were developed by the Department of Energy for the Modular Accident Analysis Package (MAAP). Calculational results of these models have been compared to the results of the Power Burst Facility Severe Fuel Damage tests. The code predictions utilizing the mass transfer correlation agreed with the experimentally determined fractional release rates during the course of the heatup, power hold, and cooldown phases of the high temperature transients. Compared to such conventional literature correlations as the steam oxidation model and the NUREG-0956 correlation, the mass transfer correlation resulted in lower and less rapid releases in closer agreement with the on-line and grab sample data from the Severe Fuel Damage tests. The proposed mass transfer correlation can be applied for best-estimate calculations of fission products release from the UO 2 fuel in both nominal and severe accident conditions. 15 refs., 10 figs., 2 tabs

  12. Expanding the power base. Building capacities for comparative energy assessment

    International Nuclear Information System (INIS)

    Hamilton, B.; Bui, D.T.; Conzelmann, G.

    2000-01-01

    Analysis of national energy systems is reaching unprecedented degrees of complexity. In addition to uncertainty of future energy demand, technology performance and costs, planners and decision makers are confronted with issues such as environment protection, sustainable development, deregulation and market liberalization. At the same time, public sector funds for energy investment projects are being progressively reduced. The IAEA offers its Member States a comprehensive programme of technical assistance and cooperation which covers many diverse areas related to peaceful uses of nuclear energy. In the area of comparative energy assessment, the objective of assistance is to strengthen national capabilities for elaborating sustainable patterns of energy supply and use. Assistance is provided in three ways, namely by: distributing state-of-the-art methodologies and decision-making tools tailored to the special needs of developing countries; providing training in model application, interpretation of results and translation into decision or policy making; and carrying out national studies in co-operation with requesting Member States

  13. What happens to the fission process above the 2nd- and 3rd-chance fission thresholds

    International Nuclear Information System (INIS)

    Stewart, L.; Howerton, R.J.

    1976-01-01

    Although the multiple fission process is important at high neutron energies, most of the evaluations available today do not include these individual fission cross sections or their associated fission spectra. The representations used in the Los Alamos and Livermore libraries are described and calculations compared with 14-MeV integral experiments available on 235 U, 238 U, and 239 Pu. Further work is needed to clearly delineate the specific problems in order to propose unique solutions

  14. A Powerful Test for Comparing Multiple Regression Functions.

    Science.gov (United States)

    Maity, Arnab

    2012-09-01

    In this article, we address the important problem of comparison of two or more population regression functions. Recently, Pardo-Fernández, Van Keilegom and González-Manteiga (2007) developed test statistics for simple nonparametric regression models: Y(ij) = θ(j)(Z(ij)) + σ(j)(Z(ij))∊(ij), based on empirical distributions of the errors in each population j = 1, … , J. In this paper, we propose a test for equality of the θ(j)(·) based on the concept of generalized likelihood ratio type statistics. We also generalize our test for other nonparametric regression setups, e.g, nonparametric logistic regression, where the loglikelihood for population j is any general smooth function [Formula: see text]. We describe a resampling procedure to obtain the critical values of the test. In addition, we present a simulation study to evaluate the performance of the proposed test and compare our results to those in Pardo-Fernández et al. (2007).

  15. Fission product behavior in the Molten Salt Reactor Experiment

    International Nuclear Information System (INIS)

    Compere, E.L.; Kirslis, S.S.; Bohlmann, E.G.; Blankenship, F.F.; Grimes, W.R.

    1975-10-01

    Essentially all the fission product data for numerous and varied samples taken during operation of the Molten Salt Reactor Experiment or as part of the examination of specimens removed after particular phases of operation are reported, together with the appropriate inventory or other basis of comparison, and relevant reactor parameters and conditions. Fission product behavior fell into distinct chemical groups. Evidence for fission product behavior during operation over a period of 26 months with 235 U fuel (more than 9000 effective full-power hours) was consistent with behavior during operation using 233 U fuel over a period of about 15 months (more than 5100 effective full-power hours)

  16. Small nuclear power reactor emergency electric power supply system reliability comparative analysis

    International Nuclear Information System (INIS)

    Bonfietti, Gerson

    2003-01-01

    This work presents an analysis of the reliability of the emergency power supply system, of a small size nuclear power reactor. Three different configurations are investigated and their reliability analyzed. The fault tree method is used as the main tool of analysis. The work includes a bibliographic review of emergency diesel generator reliability and a discussion of the design requirements applicable to emergency electrical systems. The influence of common cause failure influences is considered using the beta factor model. The operator action is considered using human failure probabilities. A parametric analysis shows the strong dependence between the reactor safety and the loss of offsite electric power supply. It is also shown that common cause failures can be a major contributor to the system reliability. (author)

  17. Theoretical model application to the evaluation of fission neutron data up to 20 MeV incidence energy

    International Nuclear Information System (INIS)

    Ruben, A.; Maerten, H.; Seeliger, D.

    1990-01-01

    A complex statistical theory of fission neutron emission combined with a phenomenological fission model has been used to calculate fission neutron data for 238 U. Obtained neutron multiplicities and energy spectra as well as average fragment energies for incidence energies from threshold to 20 MeV (including multiple-chance fission) are compared with traditional data representations. (author). 19 refs, 6 figs

  18. Opimization of fusion-driven fissioning systems

    International Nuclear Information System (INIS)

    Chapin, D.L.; Mills, R.G.

    1976-01-01

    Potential advantages of hybrid or fusion/fission systems can be exploited in different ways. With selection of the 238 U-- 239 Pu fuel cycle, we show that the system has greatest value as a power producer. Numerical examples of relative revenue from power production vs. 239 Pu production are discussed, and possible plant characteristics described. The analysis tends to show that the hybrid may be more economically attractive than pure fusion systems

  19. Fission, fusion and the energy crisis

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, S E [Aston Univ., Birmingham (UK)

    1980-01-01

    The subject is covered in chapters, entitled: living on capital (energy reserves and consumption forecasts); the atom and its nucleus, mass and energy; fission and the bomb; the natural uranium reactor; enriched reactors; control and safety; long-term economics (the breeder reactions and nuclear fuel reserves); short-term economics (cost per kilowatt hour); national nuclear power programmes; nuclear power and the environment (including reprocessing, radioactive waste management, public relations); renewable energy sources; the fusion programme; summary and comment.

  20. Fission cross sections in the intermediate energy region

    International Nuclear Information System (INIS)

    Lisowski, P.W.; Gavron, A.; Parker, W.E.; Ullmann, J.L.; Balestrini, S.J.; Carlson, A.D.; Wasson, O.A.; Hill, N.W.

    1991-01-01

    Until recently there has been very little cross section data for neutron-induced fission in the intermediate energy region, primarily because no suitable neutron source has existed. At Los Alamos, the WNR target-4 facility provides a high-intensity source of neutrons nearly ideal for fission measurements extending from a fraction of a MeV to several hundred MeV. This paper summarizes the status of fission cross section data in the intermediate energy range (En > 30 MeV) and presents our fission cross section data for 235 U and 238 U compared to intranuclear cascade and statistical model predictions

  1. The status of fission product yield data (FPND) in 1977

    International Nuclear Information System (INIS)

    Cuninghame, J.G.

    1977-05-01

    The topics covered is this paper are:- (a) cumulative yields in thermal neutron fission and in fast fission up to 14 MeV incident neutron energy; (b) dependence of the yields on incident neutron energy and spectrum; (c) independent yields; (d) charge dispersion and distribution, and (e) yields of light particles from ternary fission. The paper reviews information on these subjects for fission of actinides from 232 Th upwards, with special emphasis on data published since the 1973 Bologna FPND Panel, compares data sets and discusses the gaps still to be found in them. (author)

  2. Fission cross sections in the intermediate energy region

    Energy Technology Data Exchange (ETDEWEB)

    Lisowski, P.W.; Gavron, A.; Parker, W.E.; Ullmann, J.L.; Balestrini, S.J. (Los Alamos National Lab., NM (USA)); Carlson, A.D.; Wasson, O.A. (National Inst. of Standards and Technology, Gaithersburg, MD (USA)); Hill, N.W. (Oak Ridge National Lab., TN (USA))

    1991-01-01

    Until recently there has been very little cross section data for neutron-induced fission in the intermediate energy region, primarily because no suitable neutron source has existed. At Los Alamos, the WNR target-4 facility provides a high-intensity source of neutrons nearly ideal for fission measurements extending from a fraction of a MeV to several hundred MeV. This paper summarizes the status of fission cross section data in the intermediate energy range (En > 30 MeV) and presents our fission cross section data for {sup 235}U and {sup 238}U compared to intranuclear cascade and statistical model predictions.

  3. Nuclear fission and neutron-induced fission cross-sections

    Energy Technology Data Exchange (ETDEWEB)

    James, G.D.; Lynn, J.E.; Michaudon, A.; Rowlands, J.; de Saussure, G.

    1981-01-01

    A general presentation of current knowledge of the fission process is given with emphasis on the low energy fission of actinide nuclei and neutron induced fission. The need for and the required accuracy of fission cross section data in nuclear energy programs are discussed. A summary is given of the steps involved in fission cross section measurement and the range of available techniques. Methods of fission detection are described with emphasis on energy dependent changed and detector efficiency. Examples of cross section measurements are given and data reduction is discussed. The calculation of fission cross sections is discussed and relevant nuclear theory including the formation and decay of compound nuclei and energy level density is introduced. A description of a practical computation of fission cross sections is given.

  4. Feasibility study of a fission supressed blanket for a tandem-mirror hybrid reactor

    International Nuclear Information System (INIS)

    Moir, R.W.; Lee, J.D.; Barr, W.L.

    1981-01-01

    A study of fission suppressed blankets for the tandem mirror not only showed such blankets to be feasible but also to be safer than fissioning blankets. Such hybrids could produce enough fissile material to support up to 17 light water reactors of the same nuclear power rating. Beryllium was compared to 7 Li for neutron multiplication; both were considered feasible but the blanket with Li produced 20% less fissile fuel per unit of nuclear power in the reactor. The beryllium resource, while possibly being too small for extensive pure fusion application, would be adequate (with carefully planned industrial expansion) for the hybrid because of the large support ratio, and hence few hybrids required. Radiation damage and coatings for beryllium remain issues to be resolved by further study and experimentation. Molten salt reprocessing was compared to aqueous solution reprocessing

  5. The evaluation for reference fission yield of 238U fission

    International Nuclear Information System (INIS)

    Liang Qichang; Liu Tingjin

    1998-01-01

    In the fission yield data evaluation and measurement, the reference yield is very important, good or poor recommended or measurement values depend upon the reference data to a great extent. According to the CRP's requirement, the evaluation of reference fission yields have been and will be carried out in CNDC, as a part of the whole work (contract No.9504/R 0 /Regular Budget Fund), the evaluation for 29 reference fission yields of 15 product nuclides from 238 U fission have been completed

  6. Insights into nuclear structure and the fission process from spontaneous fission

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, J.H.; Butler-Moore, K.; Ramayya, A.V. [Vanderbilt Univ., Nashville, TN (United States)] [and others

    1993-12-31

    The {gamma}-rays emitted following spontaneous and induced fission are rich sources of information about the structure of neutron-rich nuclei and about the fission process itself. The study of spontaneous fissioning isotopes with large Ge detector arrays are providing a wealth of such information as seen, for example, in recent reports. In this paper we present some of our most recent results on nuclear structure studies and conclusions on the fission process itself. In our work, we have employed in spontaneous fission, a triple gamma coincidence study for the first time and a high resolution, X-ray detector-{gamma}-coincidence study. These data provide powerful ways of separating the gamma rays which belong to a particular nucleus. The triple coincidence technique was used to uniquely identify the levels in {sup 136}Te and higher spin states in its N=84 isotones, {sup 138}Xe and {sup 140}Ba{sup 171}. Some other examples of the level structures observed in the low and high mass partners are presented, including a detailed analysis of the backbending of the moment of inertia in {sup 112,114,116}Pd. Finally, we present the first examples of how our analysis allows one to extract a detailed picture of the dependence of the angular momentum on the mass and atomic numbers of the fission fragments and of the long-sought neutron multiplicity distribution from zero-n to ten-n as a function of the charge and mass asymmetry.

  7. Fission product detection

    International Nuclear Information System (INIS)

    Liatard, E.; Akrouf, S.; Bruandet, J.F

    1987-01-01

    The response of photovoltaic cells to heavy ions and fission products have been tested on beam. Their main advantages are their extremely low price, their low sensitivity to energetic light ions with respect to fission products, and the possibility to cut and fit them together to any shape without dead zone. The time output signals of a charge sensitive preamplifier connected to these cells allows fast coincidences. A resolution of 12ns (F.W.H.M.) have been measured between two cells [fr

  8. Fission of heavy hypernuclei

    International Nuclear Information System (INIS)

    Nifenecker, H.

    1993-01-01

    The results on delayed and prompt fission of heavy hypernuclei obtained by the LEAR PS177 collaboration are recalled and discussed. It is shown that the hypernuclei life-times can be explained in term of a weak strangeness violating lambda-nucleon interaction with a cross section close to 6.0 10 -15 barns. The lambda attachment function is shown to be sensitive to the scission configuration, just before fission, and to the neck dynamics. This function provides a new way to study the nuclear scission process. (author)

  9. Fission gas measuring technology

    International Nuclear Information System (INIS)

    Lee, Hyung Kwon; Kim, Eun Ka; Hwang, Yong Hwa; Lee, Eun Pyo; Chun, Yong Bum; Seo, Ki Seog; Park, Dea Gyu; Chu, Yong Sun; Ahn, Sang Bok.

    1998-02-01

    Safety and economy of nuclear plant are greatly affected by the integrity of nuclear fuels during irradiation reactor core. A series of post-irradiation examination (PIE) including non-destructive and destructive test is to be conducted to evaluate and characterize the nuclear performance. In this report, a principle of the examination equipment to measure and analyse fission gases existing nuclear fuels were described and features of the component and device consisting the fission gas measuring equipment are investigated. (author). 4 refs., 2 tabs., 6 figs

  10. Fission gas measuring technology

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyung Kwon; Kim, Eun Ka; Hwang, Yong Hwa; Lee, Eun Pyo; Chun, Yong Bum; Seo, Ki Seog; Park, Dea Gyu; Chu, Yong Sun; Ahn, Sang Bok

    1998-02-01

    Safety and economy of nuclear plant are greatly affected by the integrity of nuclear fuels during irradiation reactor core. A series of post-irradiation examination (PIE) including non-destructive and destructive test is to be conducted to evaluate and characterize the nuclear performance. In this report, a principle of the examination equipment to measure and analyse fission gases existing nuclear fuels were described and features of the component and device consisting the fission gas measuring equipment are investigated. (author). 4 refs., 2 tabs., 6 figs.

  11. Fission modelling with FIFRELIN

    International Nuclear Information System (INIS)

    Litaize, Olivier; Serot, Olivier; Berge, Leonie

    2015-01-01

    The nuclear fission process gives rise to the formation of fission fragments and emission of particles (n,γ, e - ). The particle emission from fragments can be prompt and delayed. We present here the methods used in the FIFRELIN code, which simulates the prompt component of the de-excitation process. The methods are based on phenomenological models associated with macroscopic and/or microscopic ingredients. Input data can be provided by experiment as well as by theory. The fission fragment de-excitation can be performed within Weisskopf (uncoupled neutron and gamma emission) or a Hauser-Feshbach (coupled neutron/gamma emission) statistical theory. We usually consider five free parameters that cannot be provided by theory or experiments in order to describe the initial distributions required by the code. In a first step this set of parameters is chosen to reproduce a very limited set of target observables. In a second step we can increase the statistics to predict all other fission observables such as prompt neutron, gamma and conversion electron spectra but also their distributions as a function of any kind of parameters such as, for instance, the neutron, gamma and electron number distributions, the average prompt neutron multiplicity as a function of fission fragment mass, charge or kinetic energy, and so on. Several results related to different fissioning systems are presented in this work. The goal in the next decade will be i) to replace some macroscopic ingredients or phenomenological models by microscopic calculations when available and reliable, ii) to be a support for experimentalists in the design of detection systems or in the prediction of necessary beam time or count rates with associated statistics when measuring fragments and emitted particle in coincidence iii) extend the model to be able to run a calculation when no experimental input data are available, iv) account for multiple chance fission and gamma emission before fission, v) account for the

  12. A new set of parameters for 5 Gaussian fission yields systematics

    International Nuclear Information System (INIS)

    Katakura, Jun-ichi

    2003-01-01

    A new set of parameters for 5 Gaussian-type fission yields systematics has been proposed for applying to high energy neutron or proton fission and to various kinds of fissioning systems including minor actinides. The mass yields calculated using the systematics were compared with various kinds of measured data including the fission with incident energy higher than 100 MeV and the fission of minor actinide nuclides. The comparisons showed rather good agreement between the calculated values and measured ones for various kinds of fissioning systems. (author)

  13. Comparing concentrating solar and nuclear power as baseload providers using the example of South Africa

    International Nuclear Information System (INIS)

    Pfenninger, Stefan; Keirstead, James

    2015-01-01

    Despite the increasing importance of variable renewable power generation, baseload, that is stable and predictable power generators, remain the backbone of many countries’ power systems. We here compare CSP (concentrating solar power) and nuclear power as baseload electricity providers for the case of South Africa, which is adding significant new generation capacity, has an abundant solar resource, but also one existing and additional planned nuclear power plants. Both of these technologies are considered baseload-capable with sufficient available fuel (sunlight or fissible material) to provide large amounts of nearly emissions-free electricity. We find that under a range of technological learning assumptions, CSP compares favorably against nuclear on costs in the period to 2030, and has lower investment and environmental risks. The results suggest that while nuclear power may be an important low-emissions power technology in regions with little sun, in the case of South Africa, CSP could be capable of providing a stable baseload supply at lower cost than nuclear power, and may have other non-cost benefits. - Highlights: • We compare nuclear and CSP (concentrating solar power) as baseload generators. • CSP could be competitive with nuclear by 2030 on providing baseload. • CSP plants producing above baseload when possible are more competitive. • On environmental and investment risks, CSP compares favorably. • Both options may have a role in different parts of the world

  14. Fission Product Library and Resource

    Energy Technology Data Exchange (ETDEWEB)

    Burke, J. T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Padgett, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-09-29

    Fission product yields can be extracted from an irradiated sample by performing gamma ray spectroscopy on the whole sample post irradiation. There are several pitfalls to avoid when trying to determine a specific isotope's fission product yield.

  15. Spontaneous fission of superheavy nuclei

    Indian Academy of Sciences (India)

    The fission-like configurations are used for the total deformation energy calculations. A ... oscillator potential for the two fission fragment regions reads as ... Beyond this limit, the contribution of more remote levels is negligible. Once the density ...

  16. Mirror fusion--fission hybrids

    International Nuclear Information System (INIS)

    Lee, J.D.

    1978-01-01

    The fusion-fission concept and the mirror fusion-fission hybrid program are outlined. Magnetic mirror fusion drivers and blankets for hybrid reactors are discussed. Results of system analyses are presented and a reference design is described

  17. Processus of fission at medium energy

    International Nuclear Information System (INIS)

    Delagrange, H.

    1977-01-01

    Excitation functions for the reactions 233 U, 234 U, 235 U( 4 He,xn)Pu have been measured radiochimically between 20 and 45 MeV. Neutron emission probabilities have been deduced from these measurements, for 239 Pu, 238 Pu. These results have been analysed in the framework of a statistical model; the double humped fission barrier has been taken into account explicitly and the parameters of the barrier extracted. In the case of heavy ion reactions, fission probabilities have been calculated with the help of the Bohr-Wheeler formula and compared to experimental data from other authors. Deduced fission parameters (asub(f)/asub(n), Bsub(f)) are compared to different theoretical models [fr

  18. Volatilization and reaction of fission products in flowing steam

    International Nuclear Information System (INIS)

    Johnson, I.; Steidl, D.V.; Johnson, C.E.

    1985-01-01

    The principal risk to the public from nuclear power plants derives from the highly radioactive atoms (fission products) generated as energy is produced in the nuclear fuel. The revolatilization of fission products from reactor system surfaces due to self-heating by radioactive decay has become a complicating factor in the source-term redefinition effort. It has had a major impact on calculations of fission product distributions in accident safety analyses. The focus of this research effort was to investigate the volatilization and transport of fission products and control rod materials in a flowing gaseous steam-hydrogen mixture. Fission product and control rod materials in various combinations were studied including CsI, CsOH, TeO 2 , SrO, Ag, In, Cd and Mn. The vaporization behavior of the deposits were characterized with respect to vaporization rates, chemical species and downstream transport behavior

  19. ISOLDE experiment explores new territory in nuclear fission

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    An international collaboration led by the University of Leuven, Belgium, exploiting ISOLDE’s radioactive beams, has recently discovered an unexpected new type of asymmetric nuclear fission, which challenges current theories. The surprising result opens the way for new nuclear structure models and further theories to elucidate the question.   Resonance Ionization Laser Ion Source (RILIS) in action at ISOLDE. RILIS was instrumental in providing the pure beam necessary for the successful nuclear fission experiment. In nuclear fission, the nucleus splits into two fragments (daughter nuclei), releasing a huge amount of energy. Nuclear fission is exploited in power plants to produce energy. From the fundamental research point of view, fission is not yet fully understood decades after its discovery and its properties can still surprise nuclear physicists. The way the process occurs can tell us a lot about the internal structure of the nucleus and the interactions taking place inside the com...

  20. Study of the number of neutrons produced by fission of 239Pu

    International Nuclear Information System (INIS)

    Jacob, M.

    1958-01-01

    Study of the number of neutrons produced by fission of 239 Pu. The counting by coincidence of fissions and neutrons produced by these fissions allows the study of the variation of the mean number of neutrons emitted by ν fission. In the first chapter, it studied the variation of the mean number of neutrons emitted by 239 Pu fission with the energy of the incident neutron. A description of the experiment is given: a spectrometer with a crystal of sodium chloride or beryllium (mounted on a goniometer) is used, a fission chamber containing 10 mg of 239 Pu and the neutron detection system constituted of BF 3 counters which are enriched in 10 B. In the second part, the counting by coincidence of fissions and neutrons produced by the same fission and received by two different groups of counters allow the determination of a relationship between the root mean square and the average of neutron number produced by fission. The variation of the mean number of neutrons emitted by fission of 239 Pu is studied when we change from a thermal spectra of neutrons to a fission spectra of incident neutrons. Finally, when separating in two different part the fission chamber, it is possible to measure the mean number of neutrons emitted from fission of two different sources. It compared the mean number of neutrons emitted by fission of 239 Pu and 233 U. (M.P.)

  1. Process for treating fission waste

    International Nuclear Information System (INIS)

    Rohrmann, C.A.; Wick, O.J.

    1983-01-01

    A method is described for the treatment of fission waste. A glass forming agent, a metal oxide, and a reducing agent are mixed with the fission waste and the mixture is heated. After melting, the mixture separates into a glass phase and a metal phase. The glass phase may be used to safely store the fission waste, while the metal phase contains noble metals recovered from the fission waste

  2. Comparative gross domestic production and electricity consumption per capita in the context of nuclear power prospect

    International Nuclear Information System (INIS)

    Ridzuan Abdul Mutalib; Maragatham Kumar; Nik Arlina Nik Ali; Abi Muttaqin Jalal Bayar; Aisya Raihan Abdul Kadir; Muhammed Zulfakar Zolkaffly; Azlinda Aziz; Jamal Khaer Ibrahim

    2008-08-01

    Malaysia, based on its economic and industrial growth level should be able to absorb nuclear technology and capacity in implementing a nuclear power programme. Malaysia Gross Domestic Production (GDP) and electricity consumption (kWh per capita is higher compared with other developing countries, which have already announced their plans to implement nuclear power programme. Furthermore, Asia reliance on nuclear power plants to meet growing energy needs in the near future is also significantly increasing. This paper presents the comparative GDP and kWh per capita in Asia and globally in the context of nuclear power prospect in Malaysia. (Author)

  3. Neutron emission during acceleration of 252Cf fission fragments

    International Nuclear Information System (INIS)

    Batenkov, O.I.; Blinov, M.V.; Blinov, A.B.; Smirnov, S.N.

    1991-01-01

    We investigate neutron emission during acceleration of fission fragments in the process of spontaneous fission of 252 Cf. Experimental angular and energy distributions of neutrons are compared with the results of calculations of neutron evaporation during fragment acceleration. (author). 8 refs, 3 figs

  4. 50 years of nuclear fission

    International Nuclear Information System (INIS)

    Hilscher, D.

    1989-01-01

    The article tells the story of the discovery of nuclear fission in Berlin 50 years ago by Otto Hahn and Fritz Strassmann in cooperation with Lise Meitner. 50 years later nuclear fission is still a subject of research. Some question remain unanswered. Selected new research results are used to discuss the dynamics of the collective movement of the elementary nuclear fission process. (orig.) [de

  5. Fission dynamics of hot nuclei

    Indian Academy of Sciences (India)

    2014-04-05

    Apr 5, 2014 ... across the fission barrier is very small or in other words, the fission barrier is much ... of this shape evolution, the gross features of the fissioning nucleus can be described ..... [7] Y Abe, C Gregoire and H Delagrange, J. Phys.

  6. Status of fission yield measurements

    International Nuclear Information System (INIS)

    Maeck, W.J.

    1979-01-01

    Fission yield measurement and yield compilation activities in the major laboratories of the world are reviewed. In addition to a general review of the effort of each laboratory, a brief summary of yield measurement activities by fissioning nuclide is presented. A new fast reactor fission yield measurement program being conducted in the US is described

  7. Specific fission J-window and angular momentum dependence of the fission barrier

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Hiroshi; Saito, Tadashi; Takahashi, Naruto; Yokoyama, Akihiko [Osaka Univ., Suita (Japan); Shinohara, Atsushi

    1997-04-01

    A method to determine a unique J-window in the fission process was devised and the fissioning nuclide associated with thus extracted J-window was identified for each of the heavy-ion reaction systems. Obtained fission barriers at the resulting J-window were compared with the calculated values by the rotating finite range model (RFRM). The deduced barriers for individual nuclides were compared with the RFRM barriers to reproduce more or less the angular momentum dependence the RFRM prediction. The deduced systematic behavior of the fission barrier indicates no even-odd and shell corrections are necessary. The nuclear dissipation effect based on Kramer`s model revealed substantial reduction of the statistically deduced barrier heights and brought a fairly large scattering from the RFRM J-dependence. However, introduction of the temperature-dependent friction coefficient ({gamma} = 2 for T {>=} 1.0 MeV and 0.5 for T < 1.0 MeV) was found to bring about satisfactory agreement with both RFRM fission barriers and the pre-fission neutron multiplicity systematics. (author). 81 refs.

  8. The fission products palladium and rhodium: Their state in solutions, their behavior in the regeneration of fuel of atomic power stations, and the search for selective extraction techniques

    International Nuclear Information System (INIS)

    Arseenkov, L.V.; Zakharkin, B.S.; Lunichkina, K.P.; Renard, E.V.; Rogozhkin, V.Yu.; Shorokhov, N.A.

    1992-01-01

    At the present time many research centers are working on the extraction of noble metals in the form of fission fragments. Consistent data has been obtained on the mass accumulation of noble metals in various forms of processed nuclear fuel. Requirements are noted that must be met for obtaining industrial and economic efficiency in the extraction of noble metals by the Purex process. Presently there is a lack of information on the extraction of noble metals from spent fuel, particularly as far as the nitric acid media of the Purex process are concerned. The authors will discuss individual test observations on simulating systems and real systems with noble metals. The investigations focused on the noble metals of lowest radioactivity, namely palladium and rhodium. The complexity of the chemistry of ruthenium, on the one hand, and the possible selective, clearing distillation of ruthenium tetroxide from nitric acid solutions, on the other hand, make it necessary to focus the attention on the unresolved problems of the extraction of palladium and rhodium. The article further includes discussion on the following topics: noble metals in solutions of purex process, electrochemical operations involving noble metals, extraction systems for rhodium and palladium, separation of palladium from real solutions

  9. The discovery of fission

    International Nuclear Information System (INIS)

    McKay, H.A.C.

    1978-01-01

    In this article by the retired head of the Separation Processes Group of the Chemistry Division, Atomic Energy Research Establishment, Harwell, U.K., the author recalls what he terms 'an exciting drama, the unravelling of the nature of the atomic nucleus' in the years before the Second World War, including the discovery of fission. 12 references. (author)

  10. Behavior of solid fission products in irradiated fuel

    International Nuclear Information System (INIS)

    Song, Ung Sup; Jung, Yang Hong; Kim, Hee Moon; Yoo, Byun Gok; Kim, Do Sik; Choo, Yong Sun; Hong, Kwon Pyo

    2004-01-01

    Many fission products are generated by fission events in UO 2 fuel under irradiation in nuclear reactor. Concentration of each fission product is changed by conditions of neutron energy spectrum, fissile material, critical thermal power, irradiation period and cooling time. Volatile materials such as Cs and I, the fission products, degrade nuclear fuel rod by the decrease of thermal conductivity in pellet and the stress corrosion cracking in cladding. Metal fission products (white inclusion) make pellet be swelled and decrease volume of pellet by densification. It seems that metal fission products are filled in the pore in pellet and placed between UO 2 lattices as interstitial. In addition, metal oxide state may change structural lattice volume. Considering behavior of fission products mentioned above, concentration of them is important. Fission products could be classified as bellows; solid solution in matrix : Sr, Zr, Nb, Y, La, Ce, Pr, Nd, Pm, Sm - metal precipitates : Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sb, Te - oxide precipitates : Ba, Zr, Nb, Mo, (Rb, Cs, Te) - volatile and gases : Kr, Xe, Br, I, (Rb, Cs, Te)

  11. Contained fissionly vaporized imploded fission explosive breeder reactor

    International Nuclear Information System (INIS)

    Marwick, E.F.

    1978-01-01

    Disclosed is a nuclear reactor system which produces useful thermal power and breeds fissile isotopes wherein large spherical complex slugs containing fissile and fertile isotopes as well as vaporizing and tamping materials are exploded seriatim in a large containing chamber having walls protected from the effects of the explosion by about two thousand tons of slurry of fissile and fertile isotopes in molten alkali metal. The slug which is slightly sub-critical prior to its entry into the centroid portion of the chamber, then becomes slightly more than prompt-critical because of the near proximity of neutron-reflecting atoms and of fissioning atoms within the slurry. The slurry is heated by explosion of the slugs and serves as a working fluid for extraction of heat energy from the reactor. Explosive debris is precipitated from the slurry and used for the fabrication of new slugs

  12. A delayed neutron technique for measuring induced fission rates in fresh and burnt LWR fuel

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, K.A., E-mail: kajordan@gmail.co [Paul Scherrer Institut, Laboratory for Reactor Physics and System Behaviour, 5232 Villigen (Switzerland); Perret, G. [Paul Scherrer Institut, Laboratory for Reactor Physics and System Behaviour, 5232 Villigen (Switzerland)

    2011-04-01

    The LIFE-PROTEUS program at the Paul Scherrer Institut is being undertaken to characterize the interfaces between burnt and fresh fuel assemblies in modern LWRs. Techniques are being developed to measure fission rates in burnt fuel following re-irradiation in the zero-power PROTEUS research reactor. One such technique utilizes the measurement of delayed neutrons. To demonstrate the feasibility of the delayed neutron technique, fresh and burnt UO{sub 2} fuel samples were irradiated in different positions in the PROTEUS reactor, and their neutron outputs were recorded shortly after irradiation. Fission rate ratios of the same sample irradiated in two different positions (inter-positional) and of two different samples irradiated in the same position (inter-sample) were derived from the measurements and compared with Monte Carlo predictions. Derivation of fission rate ratios from the delayed neutron measured signal requires correcting the signal for the delayed neutron source properties, the efficiency of the measurement setup, and the time dependency of the signal. In particular, delayed neutron source properties strongly depend on the fissile and fertile isotopes present in the irradiated sample and must be accounted for when deriving inter-sample fission rate ratios. Measured inter-positional fission rate ratios generally agree within 1{sigma} uncertainty (on the order of 1.0%) with the calculation predictions. For a particular irradiation position, however, a bias of about 2% is observed and is currently under investigation. Calculated and measured inter-sample fission rate ratios have C/E values deviating from unity by less than 1% and within 2{sigma} of the statistical uncertainties. Uncertainty arising from delayed neutron data is also assessed, and is found to give an additional 3% uncertainty factor. The measurement data indicate that uncertainty is overestimated.

  13. Correlation of recent fission product release data

    International Nuclear Information System (INIS)

    Kress, T.S.; Lorenz, R.A.; Nakamura, T.; Osborne, M.F.

    1989-01-01

    For the calculation of source terms associated with severe accidents, it is necessary to model the release of fission products from fuel as it heats and melts. Perhaps the most definitive model for fission product release is that of the FASTGRASS computer code developed at Argonne National Laboratory. There is persuasive evidence that these processes, as well as additional chemical and gas phase mass transport processes, are important in the release of fission products from fuel. Nevertheless, it has been found convenient to have simplified fission product release correlations that may not be as definitive as models like FASTGRASS but which attempt in some simple way to capture the essence of the mechanisms. One of the most widely used such correlation is called CORSOR-M which is the present fission product/aerosol release model used in the NRC Source Term Code Package. CORSOR has been criticized as having too much uncertainty in the calculated releases and as not accurately reproducing some experimental data. It is currently believed that these discrepancies between CORSOR and the more recent data have resulted because of the better time resolution of the more recent data compared to the data base that went into the CORSOR correlation. This document discusses a simple correlational model for use in connection with NUREG risk uncertainty exercises. 8 refs., 4 figs., 1 tab

  14. Rupture of the neck in nuclear fission

    International Nuclear Information System (INIS)

    Davies, K.T.R.; Managan, R.A.; Nix, J.R.; Sierk, A.J.

    1977-01-01

    We introduce a degree of freedom to describe the rupture of the neck in nuclear fission and calculate the point at which the neck ruptures as the nucleus descends dynamically from its fission saddle point. This is done by mentally slicing the system into two portions at its minimum neck radius and calculating the force required to separate the two portions while keeping their shapes fixed. This force is obtained by differentiating with respect to separation the sum of the Coulomb and nuclear interaction energies between the two portions. For nuclei throughout the Periodic Table we calculate this force along dynamical paths leading from the fission saddle point. The force is initially attractive but becomes repulsive when the neck reaches a critical size. For actinide nuclei the neck radius at which rupture occurs is about 2 fm. This increases the calculated translational kinetic energy of the fission fragments at infinity relative to that calculated for scission occurring at zero neck radius. With the effect of neck rupture taken into account, we calculate and compare with experimental results fission-fragment kinetic energies for two types of nuclear dissipation: ordinary two-body viscosity and one-body dissipation

  15. Joint ICFRM-14 (14. international conference on fusion reactor materials) and IAEA satellite meeting on cross-cutting issues of structural materials for fusion and fission applications. PowerPoint presentations

    International Nuclear Information System (INIS)

    2009-01-01

    The Conference was devoted to the challenges in the development of new materials for advanced fission, fusion and hybrid reactors. The topics discussed include fuels and materials research under the high neutron fluence; post-irradiation examination; development of radiation resistant structural materials utilizing fission research reactors; core materials development for the advanced fuel cycle initiative; qualification of structural materials for fission and fusion reactor systems; application of charged particle accelerators for radiation resistance investigations of fission and fusion structural materials; microstructure evolution in structural materials under irradiation; ion beams and ion accelerators

  16. Elastocapillary Instability in Mitochondrial Fission

    Science.gov (United States)

    Gonzalez-Rodriguez, David; Sart, Sébastien; Babataheri, Avin; Tareste, David; Barakat, Abdul I.; Clanet, Christophe; Husson, Julien

    2015-08-01

    Mitochondria are dynamic cell organelles that constantly undergo fission and fusion events. These dynamical processes, which tightly regulate mitochondrial morphology, are essential for cell physiology. Here we propose an elastocapillary mechanical instability as a mechanism for mitochondrial fission. We experimentally induce mitochondrial fission by rupturing the cell's plasma membrane. We present a stability analysis that successfully explains the observed fission wavelength and the role of mitochondrial morphology in the occurrence of fission events. Our results show that the laws of fluid mechanics can describe mitochondrial morphology and dynamics.

  17. A threshold for dissipative fission

    International Nuclear Information System (INIS)

    Thoennessen, M.; Bertsch, G.F.

    1993-01-01

    The empirical domain of validity of statistical theory is examined as applied to fission data on pre-fission data on pre-fission neutron, charged particle, and γ-ray multiplicities. Systematics are found of the threshold excitation energy for the appearance of nonstatistical fission. From the data on systems with not too high fissility, the relevant phenomenological parameter is the ratio of the threshold temperature T thresh to the (temperature-dependent) fission barrier height E Bar (T). The statistical model reproduces the data for T thresh /E Bar (T) thresh /E Bar (T) independent of mass and fissility of the systems

  18. Correlated Production and Analog Transport of Fission Neutrons and Photons using Fission Models FREYA, FIFRELIN and the Monte Carlo Code TRIPOLI-4® .

    Science.gov (United States)

    Verbeke, Jérôme M.; Petit, Odile; Chebboubi, Abdelhazize; Litaize, Olivier

    2018-01-01

    Fission modeling in general-purpose Monte Carlo transport codes often relies on average nuclear data provided by international evaluation libraries. As such, only average fission multiplicities are available and correlations between fission neutrons and photons are missing. Whereas uncorrelated fission physics is usually sufficient for standard reactor core and radiation shielding calculations, correlated fission secondaries are required for specialized nuclear instrumentation and detector modeling. For coincidence counting detector optimization for instance, precise simulation of fission neutrons and photons that remain correlated in time from birth to detection is essential. New developments were recently integrated into the Monte Carlo transport code TRIPOLI-4 to model fission physics more precisely, the purpose being to access event-by-event fission events from two different fission models: FREYA and FIFRELIN. TRIPOLI-4 simulations can now be performed, either by connecting via an API to the LLNL fission library including FREYA, or by reading external fission event data files produced by FIFRELIN beforehand. These new capabilities enable us to easily compare results from Monte Carlo transport calculations using the two fission models in a nuclear instrumentation application. In the first part of this paper, broad underlying principles of the two fission models are recalled. We then present experimental measurements of neutron angular correlations for 252Cf(sf) and 240Pu(sf). The correlations were measured for several neutron kinetic energy thresholds. In the latter part of the paper, simulation results are compared to experimental data. Spontaneous fissions in 252Cf and 240Pu are modeled by FREYA or FIFRELIN. Emitted neutrons and photons are subsequently transported to an array of scintillators by TRIPOLI-4 in analog mode to preserve their correlations. Angular correlations between fission neutrons obtained independently from these TRIPOLI-4 simulations, using

  19. Regulatory simplification of fission product chemistry

    International Nuclear Information System (INIS)

    Read, J.B.J.; Soffer, L.

    1986-01-01

    The requirements for design provisions intended to limit fission product escape during reactor accidents have been based since 1962 upon a small number of simply-stated assumptions. These assumptions permeate current reactor regulation, but are too simple to deal with the complex processes that can reasonably be expected to occur during real accidents. Potential chemical processes of fission products in severe accidents are compared with existing plant safety features designed to minimize off-site consequences, and the possibility of a new set of simply-stated assumptions to replace the 1982 set is discussed

  20. Obsidian dating by fission track method

    International Nuclear Information System (INIS)

    Araya, A.M.O.

    1990-12-01

    The fission track method was employed to obtain the age of twelve obsidian sample from Ecuador. By using the plateau-age correction method, we obtained the true age of each sample and were able to identify four groups of ages in the studied area. Thereafter we studied the fading of fission tracks in two obsidian samples with different origins: Yanaurcu, Ecuador and Monte Arci, Italy. We constructed Arrhenius plots and calculated activation energies for both samples. The results from thermal annealing experiments were compared with theoretical curves obtained by integrating an equation proposed by Shukolyukov et al (1965). (author). 43 refs, 20 figs, 10 tabs

  1. Fission products in glasses. Pt. 2

    International Nuclear Information System (INIS)

    De, A.K.; Luckscheiter, B.; Malow, G.; Schiewer, E.

    1977-09-01

    Glass ceramics of different composition with high leach and impact resistance can be produced for fission product solidification. In contrast to commercial glass products, they consist of a number of crystalline phases and a residual glass phase. The major crystalline phase allows a classification into celsian, diopside, encryptite, and perovskite ceramics. They all are of special importance as host phases for long-lived fission products. The paper reports on relations between product composition and melting properties, viscosity, crystallization properties, and fixation capability for fission products. Further investigations deal with dimensional stability, impact resistance, thermal expansion, and thermal conductivity. The properties of the ceramics are compared with those of the basic products. The problems still to be solved with regard to further improvement and application of these products are discussed. (RB) [de

  2. A Method to Compare the Descriptive Power of Different Types of Petri Nets

    DEFF Research Database (Denmark)

    Jensen, Kurt

    1980-01-01

    The purpose of this paper is to show how the descriptive power of different types of Petri nets can be compared, without the use of Petri net languages. Moreover the paper proposes an extension of condition/event-nets and it is shown that this extension has the same descriptive power as condition/event-nets....

  3. Barium 139 as Fission Indicator

    Energy Technology Data Exchange (ETDEWEB)

    Broda, E.

    1943-07-01

    This report is based on a measurement performed at the Cavendish Laboratory (Cambridge) by E. Broda in December 1943 where a technique has been worked out for measuring the fission density in a uranium containing medium in relative units by determining the amount of a suitable fission product formed. Generally a given fission product will be formed in natural uranium by slow neutron fission of U235 or by fast neutron fission of either U235 or U238. It is intended to translate the relative units into absolute units by comparison of the Ba yield with the indication of UF6 fission chamber in the same medium. This has to be done separately for fast and slow neutron fission as the yields may be different. Another application of the technique developed is the measurement of thermal neutron density in an uraniferous medium without using a detector subject to variations of sensitivity according to the properties of the medium. (nowak)

  4. Sensitivity analysis for CORSOR models simulating fission product release in LOFT-LP-FP-2 severe accident experiment

    Energy Technology Data Exchange (ETDEWEB)

    Hoseyni, Seyed Mohsen [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Dept. of Basic Sciences; Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Young Researchers and Elite Club; Pourgol-Mohammad, Mohammad [Sahand Univ. of Technology, Tabriz (Iran, Islamic Republic of). Dept. of Mechanical Engineering; Yousefpour, Faramarz [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of)

    2017-03-15

    This paper deals with simulation, sensitivity and uncertainty analysis of LP-FP-2 experiment of LOFT test facility. The test facility simulates the major components and system response of a pressurized water reactor during a LOCA. MELCOR code is used for predicting the fission product release from the core fuel elements in LOFT LP-FP-2 experiment. Moreover, sensitivity and uncertainty analysis is performed for different CORSOR models simulating release of fission products in severe accident calculations for nuclear power plants. The calculated values for the fission product release are compared under different modeling options to the experimental data available from the experiment. In conclusion, the performance of 8 CORSOR modeling options is assessed for available modeling alternatives in the code structure.

  5. Geology behind nuclear fission technology

    International Nuclear Information System (INIS)

    Dhana Raju, R.

    2005-01-01

    Geology appears to have played an important role of a precursor to Nuclear Fission Technology (NFT), in the latter's both birth from the nucleus of an atom of and most important application as nuclear power extracted from Uranium (U), present in its minerals. NFT critically depends upon the availability of its basic raw material, viz., nuclear fuel as U and/ or Th, extracted from U-Th minerals of specific rock types in the earth's crust. Research and Development of the Nuclear Fuel Cycle (NFC) depends heavily on 'Geology'. In this paper, a brief review of the major branches of geology and their contributions during different stages of NFC, in the Indian scenario, is presented so as to demonstrate the important role played by 'Geology' behind the development of NFT, in general, and NFC, in particular. (author)

  6. Extraction of potential energy in charge asymmetry coordinate from experimental fission data

    Energy Technology Data Exchange (ETDEWEB)

    Pasca, H. [Joint Institute for Nuclear Research, Dubna (Russian Federation); ' ' Babes-Bolyai' ' Univ., Cluj-Napoca (Romania); Andreev, A.V.; Adamian, G.G. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Antonenko, N.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Tomsk Polytechnic Univ. (Russian Federation). Mathematical Physics Dept.

    2016-12-15

    For fissioning isotopes of Ra, Ac, Th, Pa, and U, the potential energies as a function of the charge asymmetry coordinate are extracted from the experimental charge distributions of the fission fragment and compared with the calculated scission-point driving potentials. The role of the potential energy surfaces in the description of the fission charge distribution is discussed. (orig.)

  7. An investigation of the statistical power of neutrality tests based on comparative and population genetic data

    DEFF Research Database (Denmark)

    Zhai, Weiwei; Nielsen, Rasmus; Slatkin, Montgomery

    2009-01-01

    In this report, we investigate the statistical power of several tests of selective neutrality based on patterns of genetic diversity within and between species. The goal is to compare tests based solely on population genetic data with tests using comparative data or a combination of comparative...... and population genetic data. We show that in the presence of repeated selective sweeps on relatively neutral background, tests based on the d(N)/d(S) ratios in comparative data almost always have more power to detect selection than tests based on population genetic data, even if the overall level of divergence...... selection. The Hudson-Kreitman-Aguadé test is the most powerful test for detecting positive selection among the population genetic tests investigated, whereas McDonald-Kreitman test typically has more power to detect negative selection. We discuss our findings in the light of the discordant results obtained...

  8. Matching of dense plasma focus devices with fission reactors

    International Nuclear Information System (INIS)

    Harms, A.A.; Heindler, M.

    1978-01-01

    The potential role of dense plasma focus devices as compact neutron sources for fissile fuel breeding in conjunction with existing fission reactors is considered. It is found that advanced plasma focus devices can be used effectively in conjunction with neutronically efficient fission reactors to constitute ''self-sufficient'' breeders. Correlations among the various parameters such as the power output and conversion ratio of the fission reactor with the neutron yield and capacitor bank energy of the dense plasma focus device are presented and discussed

  9. Fission product yield measurements using monoenergetic photon beams

    Science.gov (United States)

    Krishichayan; Bhike, M.; Tonchev, A. P.; Tornow, W.

    2017-09-01

    Measurements of fission products yields (FPYs) are an important source of information on the fission process. During the past couple of years, a TUNL-LANL-LLNL collaboration has provided data on the FPYs from quasi monoenergetic neutron-induced fission on 235U, 238U, and 239Pu and has revealed an unexpected energy dependence of both asymmetric fission fragments at energies below 4 MeV. This peculiar FPY energy dependence was more pronounced in neutron-induced fission of 239Pu. In an effort to understand and compare the effect of the incoming probe on the FPY distribution, we have carried out monoenergetic photon-induced fission experiments on the same 235U, 238U, and 239Pu targets. Monoenergetic photon beams of Eγ = 13.0 MeV were provided by the HIγS facility, the world's most intense γ-ray source. In order to determine the total number of fission events, a dual-fission chamber was used during the irradiation. These irradiated samples were counted at the TUNL's low-background γ-ray counting facility using high efficient HPGe detectors over a period of 10 weeks. Here we report on our first ever photofission product yield measurements obtained with monoenegetic photon beams. These results are compared with neutron-induced FPY data.

  10. Fission product yield measurements using monoenergetic photon beams

    Directory of Open Access Journals (Sweden)

    Krishichayan

    2017-01-01

    Full Text Available Measurements of fission products yields (FPYs are an important source of information on the fission process. During the past couple of years, a TUNL-LANL-LLNL collaboration has provided data on the FPYs from quasi monoenergetic neutron-induced fission on 235U, 238U, and 239Pu and has revealed an unexpected energy dependence of both asymmetric fission fragments at energies below 4 MeV. This peculiar FPY energy dependence was more pronounced in neutron-induced fission of 239Pu. In an effort to understand and compare the effect of the incoming probe on the FPY distribution, we have carried out monoenergetic photon-induced fission experiments on the same 235U, 238U, and 239Pu targets. Monoenergetic photon beams of Eγ = 13.0 MeV were provided by the HIγS facility, the world's most intense γ-ray source. In order to determine the total number of fission events, a dual-fission chamber was used during the irradiation. These irradiated samples were counted at the TUNL's low-background γ-ray counting facility using high efficient HPGe detectors over a period of 10 weeks. Here we report on our first ever photofission product yield measurements obtained with monoenegetic photon beams. These results are compared with neutron-induced FPY data.

  11. A comparative study of voltage stability indices in a power system

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, A.K. [I.I.T., Kharagpur (India). Dept. of Electrical Engineering; Hazarika, D. [Assam Engineering College (India)

    2000-11-01

    The paper compares the effectiveness of voltage stability indices in providing information about the proximity of voltage instability of a power system. Three simple voltage stability indices are proposed and their effectiveness is compared with some of the recently proposed indices. The comparison is carried out over a wide range of system operating conditions by changing the load power factor and feeder X/R ratios. Test results for the IEEE 57 bus and IEEE 118 bus system are presented. (author)

  12. A comparative analysis of the domestic and foreign licensing processes for power and non-power reactors

    International Nuclear Information System (INIS)

    Joe, J. C.; Youn, Y. K.; Kim, W. S.; Kim, H. J.

    2003-01-01

    The System-integrated Modular Advanced Reactor (SMART), a small to medium sized integral type Pressurized Water Reactor (PWR) has been developed in Korea. Now, SMART-P, a 1/5 scaled-down of the SMART, is being developed for the purpose of demonstrating the safety and performance of SMART design. The SMART-P is a first-of-a-kind reactor which is utilized for the research and development of a power reactor. Since the licensing process of such a reactor is not clearly specified in the current Atomic Energy Act, a comparative survey and analysis of domestic and foreign licensing processes for power and non-power reactors has been carried out to develop the rationale and technical basis for establishing the licensing process of such a reactor. The domestic and foreign licensing processes of power and non-power reactors have been surveyed and compared, including those of the U.S.A., Japan, France, U.K., Canada, and IAEA. The general trends in nuclear reactor classification, licensing procedures, regulatory technical requirements, and other licensing requirements and regulations have been investigated. The results of this study will be used as the rationale and technical basis for establishing the licensing process of reactors at development stage such as SMART-P

  13. Fission neutron spectra measurements at LANSCE - status and plans

    International Nuclear Information System (INIS)

    Haight, Robert C.; Noda, Shusaku; Nelson, Ronald O.; O' Donnell, John M.; Devlin, Matt; Chatillon, Audrey; Granier, Thierry; Taieb, Julien; Laurent, Benoit; Belier, Gilbert; Becker, John A.; Wu, Ching-Yen

    2009-01-01

    A program to measure fission neutron spectra from neutron-induced fission of actinides is underway at the Los Alamos Neutron Science Center (LANSCE) in a collaboration among the CEA laboratory at Bruyeres-le-Chatel, Lawrence Livermore National Laboratory and Los Alamos National Laboratory. The spallation source of fast neutrons at LANSCE is used to provide incident neutron energies from less than 1 MeV to 100 MeV or higher. The fission events take place in a gas-ionization fission chamber, and the time of flight from the neutron source to that chamber gives the energy of the incident neutron. Outgoing neutrons are detected by an array of organic liquid scintillator neutron detectors, and their energies are deduced from the time of flight from the fission chamber to the neutron detector. Measurements have been made of the fission neutrons from fission of 235 U, 238 U, 237 Np and 239 Pu. The range of outgoing energies measured so far is from 1 MeV to approximately 8 MeV. These partial spectra and average fission neutron energies are compared with evaluated data and with models of fission neutron emission. Results to date will be presented and a discussion of uncertainties will be given in this presentation. Future plans are to make significant improvements in the fission chambers, neutron detectors, signal processing, data acquisition and the experimental environment to provide high fidelity data including mea urements of fission neutrons below 1 MeV and improvements in the data above 8 MeV.

  14. Fission and r-process nucleosynthesis in neutron star mergers

    International Nuclear Information System (INIS)

    Giuliani, Samuel Andrea

    2018-01-01

    rates are used in r-process calculations for matter dynamically ejected in neutron star mergers and we compare our results with those obtained from a more conventional set of reaction rates. We find that all the models predict the onset of fission above the shell closure N=184 and Z=100 due to the sudden decrease in fission barriers. However, the amount of material accumulated at N=184 turns out to be very sensitive to the height of the fission barriers and the shell gap. Finally, we have also explored the impact of recent advances in fission calculations on the theoretical estimation of spontaneous fission lifetimes. We find that performing dynamical approaches based on the minimization of the integral action with nontraditional collective degrees of freedom has a strong impact in the fission barriers and the spontaneous fission lifetimes. The possible consequences of this new approach for the calculation of neutron induced fission rates has to be addressed.

  15. The fission track method

    International Nuclear Information System (INIS)

    Hansen, K.

    1990-01-01

    During the last decade fission track (FT) analysis has evolved as an important tool in exploration for hydrocarbon resources. Most important is this method's ability to yield information about temperatures at different times (history), and thus relate oil generation and time independently of other maturity parameters. The purpose of this paper is to introduce the basics of the method and give an example from the author's studies. (AB) (14 refs.)

  16. [Fission product yields of 60 fissioning reactions]. Final report

    International Nuclear Information System (INIS)

    Rider, B.F.

    1995-01-01

    In keeping with the statement of work, I have examined the fission product yields of 60 fissioning reactions. In co-authorship with the UTR (University Technical Representative) Talmadge R. England ''Evaluation and Compilation of Fission Product Yields 1993,'' LA-UR-94-3106(ENDF-349) October, (1994) was published. This is an evaluated set of fission product Yields for use in calculation of decay heat curves with improved accuracy has been prepared. These evaluated yields are based on all known experimental data through 1992. Unmeasured fission product yields are calculated from charge distribution, pairing effects, and isomeric state models developed at Los Alamos National Laboratory. The current evaluation has been distributed as the ENDF/B-VI fission product yield data set

  17. Radioactive ion beams produced by neutron-induced fission at ISOLDE

    CERN Document Server

    Catherall, R; Gilardoni, S S; Köster, U

    2003-01-01

    The production rates of neutron-rich fission products for the next-generation radioactive beam facility EURISOL are mainly limited by the maximum amount of power deposited by protons in the target. An alternative approach is to use neutron beams to induce fission in actinide targets. This has the advantage of reducing: the energy deposited by the proton beam in the target; contamination from neutron-deficient isobars that would be produced by spallation; and mechanical stress on the target. At ISOLDE CERN, tests have been made on standard ISOLDE actinide targets using fast neutron bunches produced by bombarding thick, high-Z metal converters with 1 and 1.4 GeV proton pulses. This paper reviews the first applications of converters used at ISOLDE. It highlights the different geometries and the techniques used to compare fission yields produced by the proton beam directly on the target with neutron-induced fission. Results from the six targets already tested, namely UC2/graphite and ThO2 targets with tungsten an...

  18. Characteristics of fission product release from a molten pool

    International Nuclear Information System (INIS)

    Yun, J.I.; Suh, K.Y.; Kang, C.S.

    2001-01-01

    The volatile fission products are released from the debris pool, while the less volatile fission products tend to remain as condensed phases because of their low vapor pressure. The release of noble gases and the volatile fission products is dominated by bubble dynamics. The release of the less volatile fission products from the pool can be analyzed based on mass transport through a liquid with the convection flow. The physico-numerical models were orchestrated from existing submodels in various disciplines of engineering to estimate the released fraction of fission products from a molten pool. It was assumed that the pool has partially filled hemispherical geometry. For the high pool pressure, the diameter of the bubbles at detachment was calculated utilizing the Cole and Shulman correlation with the effect of system pressure. Sensitivity analyses were performed and results of the numerical calculations were compared with analysis results for the TMI-2 accident. (author)

  19. Aerosols and fission product transport

    International Nuclear Information System (INIS)

    Megaw, W.J.

    1987-12-01

    A survey is presented of current knowledge of the possible role of aerosols in the consequences of in- and out-of-core LOCAs and of end fitting failures in CANDU reactors. An extensive literature search has been made of research on the behaviour of aerosols in possible accidents in water moderated and cooled reactors and the results of various studies compared. It is recommended that further work should be undertaken on the formation of aerosols during these possible accidents and to study their subsequent behaviour. It is also recommended that the fission products behaviour computer code FISSCON II should be re-examined to determine whether it reflects the advances incorporated in other codes developed for light water reactors which have been extensively compared. 47 refs

  20. Fission Evaluation on Th-232

    International Nuclear Information System (INIS)

    Lee, Yong-Deok; Lee, Young-Ouk; Park, Joo-Hwan

    2007-01-01

    In recent years, several studies of neutron induced reaction on thorium were carried out in the framework of an IAEA coordinate research project involving a US contribution. The importance of Th-232 is for an innovative fuel cycle concept based on thorium fuel. Thorium fuels are also considered in accelerator driven system (ADS) to produce the power and radioactive waste transmutation. Therefore, the accurate neutron cross section for fission is crucially important for the design of various reactor systems. On December 2006, the ENDF/B-VII involving the new evaluation of actinides for Th-U fuel cycle was released. From the current environmental change, increasing oil price, air pollution by carbon dioxide, drain of oil resource, increasing demand of electricity, and energy independence, nuclear power is slowly to start to be reconsidered recently and it might be an alternative proposal as a production facility of energy and a reuse of resources. Even though it produces the nuclear wastes, it has an advantage in the emission of greenhouse gases. Therefore, new concept of nuclear technology to be developed for power production is subject to the condition of increased safety, reduction of nuclear wastes, resistance to nuclear material proliferation, Thorium fuel cycle is the most feasible option to satisfy the condition. Specially, thorium reserves are much larger than those of uranium

  1. Coulomb fission and transfer fission at heavy ion collisions

    International Nuclear Information System (INIS)

    Himmele, G.

    1981-01-01

    In the present thesis the first direct evidence of nuclear fission after inelastic scattering of heavy ions (sup(183,184)W, 152 Sm → 238 U; 184 W → 232 Th; 184 W, 232 Th → 248 Cm) is reported. Experiments which were performed at the UNILAC of the Gesellschaft fuer Schwerionenforschung in Darmstadt show the observed heavy ion induced fission possesses significant properties of the Coulomb fission. The observed dependence of the fission probability for inelastic scattering on the projectile charge proves that the nuclear fission is mediated by the electromagnetic interaction between heavy ions. This result suggests moreover a multiple Coulomb-excitation preceding the fission. Model calculations give a first indication, that the Coulomb fission proceeds mainly from the higher β phonons. In the irradiation with 184 W the fission probability of 232 Th is for all incident energies about 40% smaller that at 238 U. The target dependence of the Coulomb fission however doesn't allow, to give quantitative statements about the position and B(E2)-values of higher lying β phonons. (orig./HSI) [de

  2. Understanding Comprehensive School Reforms: Insights from Comparative-Historical Sociology and Power Resources Theory

    Science.gov (United States)

    Sass, Katharina

    2015-01-01

    The historical origins and development of comprehensive schooling have seldom been analyzed systematically and comparatively. However, there is a rich comparative and historically grounded literature on the development of welfare states, which focuses on many relevant policies, but ignores the education system. In particular, the power resources…

  3. Using Data-Mining Approaches for Wind Turbine Power Curve Monitoring: A Comparative Study

    DEFF Research Database (Denmark)

    Schlechtingen, Meik; Santos, Ilmar; Achiche, Sofiane

    2013-01-01

    are built and their performance compared against literature. Recently developed adaptive neuro-fuzzy-interference system models are set up and their performance compared with the other models, using the same data. Literature models often neglect the influence of the ambient temperature and the wind...... direction. The ambient temperature can influence the power output up to 20%. Nearby obstacles can lower the power output for certain wind directions. The approaches proposed in literature and the ANFIS models are compared by using wind speed only and two additional inputs. The comparison is based...

  4. Studies of Fission Fragment Rocket Engine Propelled Spacecraft

    Science.gov (United States)

    Werka, Robert O.; Clark, Rodney; Sheldon, Rob; Percy, Thomas K.

    2014-01-01

    vehicles are very large, they are primarily made up of a habitat payload on one end, the engine on the opposite end and a connecting spine containing radiator acreage needed to reject the heat of this powerful, but inefficient engine. These studies concluded that the engine and spacecraft are within today's technology, could be built, tested, launched on several SLS launchers, integrated, checked out, maintained at an in-space LEO base, and operated for decades just as Caribbean cruise ships operate today. The nuclear issues were found to be far less daunting that [than for] current nuclear engines. The FFRE produces very small amounts of radioactive efflux compared to their impulse, easily contained in an evacuated "bore-hole" test site. The engine poses no launch risk since it is simply a structure containing no fissionable material. The nuclear fuel is carried to orbit in containers highly crash-proofed for launch accidents from which it, in a liquid medium, is injected into the FFRE. The radioactive exhaust, with a velocity above 300 kilometers per second rapidly leaves the solar system.

  5. Axisymmetric Magnetic Mirror Fusion-Fission Hybrid

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Martovetsky, N. N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Molvik, A. W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ryutov, D. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Simonen, T. C. [Univ. of California, Berkeley, CA (United States)

    2011-05-13

    The achieved performance of the gas dynamic trap version of magnetic mirrors and today’s technology we believe are sufficient with modest further efforts for a neutron source for material testing (Q=Pfusion/Pinput~0.1). The performance needed for commercial power production requires considerable further advances to achieve the necessary high Q>>10. An early application of the mirror, requiring intermediate performance and intermediate values of Q~1 are the hybrid applications. The Axisymmetric Mirror has a number of attractive features as a driver for a fusion-fission hybrid system: geometrical simplicity, inherently steady-state operation, and the presence of the natural divertors in the form of end tanks. This level of physics performance has the virtue of low risk and only modest R&D needed and its simplicity promises economy advantages. Operation at Q~1 allows for relatively low electron temperatures, in the range of 4 keV, for the DT injection energy ~ 80 keV. A simple mirror with the plasma diameter of 1 m and mirror-to-mirror length of 35 m is discussed. Simple circular superconducting coils are based on today’s technology. The positive ion neutral beams are similar to existing units but designed for steady state. A brief qualitative discussion of three groups of physics issues is presented: axial heat loss, MHD stability in the axisymmetric geometry, microstability of sloshing ions. Burning fission reactor wastes by fissioning actinides (transuranics: Pu, Np, Am, Cm, .. or just minor actinides: Np, Am, Cm, …) in the hybrid will multiply fusion’s energy by a factor of ~10 or more and diminish the Q needed to less than 1 to overcome the cost of recirculating power for good economics. The economic value of destroying actinides by fissioning is rather low based on either the cost of long-term storage or even deep geologic disposal so most of the revenues of hybrids will come from electrical power. Hybrids that obtain revenues from

  6. A Comparative Perspective on the Social Representation of Political Power by Gender

    Directory of Open Access Journals (Sweden)

    Mihaela Rus

    2015-12-01

    Full Text Available Refined and institutionalized as an expression in the human world, however, power is not a human invention. For many species, power relationships are an intra-and inter -generational stake and strictly configure their daily life. There is no wonder that ethology places the idea of power among the primary aspects of social life and, together with evolutionary psychology, submits it to comparative analyzes at human - infrahuman levels, representing thus an inexhaustible research on the meaning and destiny of power. Inevitably, through the priority directions of social psychology such as social influence, interpersonal or intergroup relations, social status and roles, social comparison, the construction of individual and collective identities etc. power issues greatly interfered with the differences between the sexes.

  7. A small flat fission chamber

    International Nuclear Information System (INIS)

    Li Yijun; Wang Dalun; Chen Suhe

    1999-01-01

    With fission materials of depleted uranium, natural uranium, enriched uranium, 239 Pu, and 237 Np, the authors have designed and made a series of small flat fission chamber. The authors narrated the construction of the fission chamber and its technological process of manufacture, and furthermore, the authors have measured and discussed the follow correct factor, self-absorption, boundary effect, threshold loss factor, bottom scatter and or so

  8. Fission barriers of light nuclei

    International Nuclear Information System (INIS)

    Grotowski, K.; Planeta, R.; Blann, M.; Komoto, T.

    1989-01-01

    Experimental fission excitation functions for compound nuclei /sup 52/Fe, /sup 49/Cr, /sup 46/V, and /sup 44/Ti formed in heavy-ion reactions are analyzed in the Hauser-Feshbach/Bohr-Wheeler formalism using fission barriers based on the rotating liquid drop model of Cohen et al. and on the rotating finite range model of Sierk. We conclude that the rotating finite range approach gives better reproduction of experimental fission yields, consistent with results found for heavier systems

  9. Nuclear Forensics and Radiochemistry: Fission

    Energy Technology Data Exchange (ETDEWEB)

    Rundberg, Robert S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-07

    Radiochemistry has been used to study fission since it’ discovery. Radiochemical methods are used to determine cumulative mass yields. These measurements have led to the two-mode fission hypothesis to model the neutron energy dependence of fission product yields. Fission product yields can be used for the nuclear forensics of nuclear explosions. The mass yield curve depends on both the fuel and the neutron spectrum of a device. Recent studies have shown that the nuclear structure of the compound nucleus can affect the mass yield distribution.

  10. Micro plate fission chamber development

    International Nuclear Information System (INIS)

    Wang Mei; Wen Zhongwei; Lin Jufang; Jiang Li; Liu Rong; Wang Dalun

    2014-01-01

    To conduct the measurement of neutron flux and the fission rate distribution at several position in assemblies, the micro plate fission chamber was designed and fabricated. Since the requirement of smaller volume and less structure material was taken into consideration, it is convinient, commercial and practical to use fission chamber to measure neutron flux in specific condition. In this paper, the structure of fission chamber and process of fabrication were introduced and performance test result was presented. The detection efficiency is 91.7%. (authors)

  11. Fusion-fission type collisions

    International Nuclear Information System (INIS)

    Oeschler, H.

    1980-01-01

    Three examples of fusion-fission type collisions on medium-mass nuclei are investigated whether the fragment properties are consistent with fission from equilibrated compound nuclei. Only in a very narrow band of angular momenta the data fulfill the necessary criteria for this process. Continuous evolutions of this mechnism into fusion fission and into a deep-inelastic process and particle emission prior to fusion have been observed. Based on the widths of the fragment-mass distributions of a great variety of data, a further criterion for the compound-nucleus-fission process is tentatively proposed. (orig.)

  12. Comparing electricity transitions: A historical analysis of nuclear, wind and solar power in Germany and Japan

    International Nuclear Information System (INIS)

    Cherp, Aleh; Vinichenko, Vadim; Jewell, Jessica; Suzuki, Masahiro; Antal, Miklós

    2017-01-01

    This paper contributes to understanding national variations in using low-carbon electricity sources by comparing the evolution of nuclear, wind and solar power in Germany and Japan. It develops and applies a framework for analyzing low-carbon electricity transitions based on interplay of techno-economic, political and socio-technical processes. We explain why in the 1970s–1980s, the energy paths of the two countries were remarkably similar, but since the 1990s Germany has become a leader in renewables while phasing out nuclear energy, whereas Japan has deployed less renewables while becoming a leader in nuclear power. We link these differences to the faster growth of electricity demand and energy insecurity in Japan, the easier diffusion of onshore wind power technology and the weakening of the nuclear power regime induced by stagnation and competition from coal and renewables in Germany. We show how these changes involve the interplay of five distinct mechanisms which may also play a role in other energy transitions. - Highlights: • We identify five mechanisms which play a role in national low-carbon electricity transitions. • Use of nuclear, wind and solar power in Germany and Japan diverged in the 1990s. • Wind power diffused to Germany from Denmark but different geography stalled it in Japan. • Demand growth and energy insecurity prompted nuclear power expansion in Japan. • Competition with domestic coal and wind led to the demise of nuclear power in Germany.

  13. Validity and reproducibility of the ErgomoPro power meter compared with the SRM and Powertap power meters.

    Science.gov (United States)

    Duc, Sebastien; Villerius, Vincent; Bertucci, William; Grappe, Frederic

    2007-09-01

    The ErgomoPro (EP) is a power meter that measures power output (PO) during outdoor and indoor cycling via 2 optoelectronic sensors located in the bottom bracket axis. The aim of this study was to determine the validity and the reproducibility of the EP compared with the SRM crank set and Powertap hub (PT). The validity of the EP was tested in the laboratory during 8 submaximal incremental tests (PO: 100 to 400 W), eight 30-min submaximal constant-power tests (PO = 180 W), and 8 sprint tests (PO > 750 W) and in the field during 8 training sessions (time: 181 +/- 73 min; PO: approximately 140 to 160 W). The reproducibility was assessed by calculating the coefficient of PO variation (CV) during the submaximal incremental and constant tests. The EP provided a significantly higher PO than the SRM and PT during the submaximal incremental test: The mean PO differences were +6.3% +/- 2.5% and +11.1% +/- 2.1% respectively. The difference was greater during field training sessions (+12.0% +/- 5.7% and +16.5% +/- 5.9%) but lower during sprint tests (+1.6% +/- 2.5% and +3.2% +/- 2.7%). The reproducibility of the EP is lower than those of the SRM and PT (CV = 4.1% +/- 1.8%, 1.9% +/- 0.4%, and 2.1% +/- 0.8%, respectively). The EP power meter appears less valid and reliable than the SRM and PT systems.

  14. Study on the effect factor of the absolute fission rates measured by depleted uranium fission chamber

    International Nuclear Information System (INIS)

    Jiang Li; Liu Rong; Wang Dalun; Wang Mei; Lin Jufang; Wen Zhongwei

    2003-01-01

    The absolute fission rates was measured by the depleted uranium fission chamber. The efficiency of the fission fragments recorded in the fission chamber was analyzed. The factor influencing absolute fission rates was studied in the experiment, including the disturbing effect between detectors and the effect of the structural of the fission chamber, etc

  15. Measurement of Fission Product Yields from Fast-Neutron Fission

    Science.gov (United States)

    Arnold, C. W.; Bond, E. M.; Bredeweg, T. A.; Fowler, M. M.; Moody, W. A.; Rusev, G.; Vieira, D. J.; Wilhelmy, J. B.; Becker, J. A.; Henderson, R.; Kenneally, J.; Macri, R.; McNabb, D.; Ryan, C.; Sheets, S.; Stoyer, M. A.; Tonchev, A. P.; Bhatia, C.; Bhike, M.; Fallin, B.; Gooden, M. E.; Howell, C. R.; Kelley, J. H.; Tornow, W.

    2014-09-01

    One of the aims of the Stockpile Stewardship Program is a reduction of the uncertainties on fission data used for analyzing nuclear test data [1,2]. Fission products such as 147Nd are convenient for determining fission yields because of their relatively high yield per fission (about 2%) and long half-life (10.98 days). A scientific program for measuring fission product yields from 235U,238U and 239Pu targets as a function of bombarding neutron energy (0.1 to 15 MeV) is currently underway using monoenergetic neutron beams produced at the 10 MV Tandem Accelerator at TUNL. Dual-fission chambers are used to determine the rate of fission in targets during activation. Activated targets are counted in highly shielded HPGe detectors over a period of several weeks to identify decaying fission products. To date, data have been collected at neutron bombarding energies 4.6, 9.0, 14.5 and 14.8 MeV. Experimental methods and data reduction techniques are discussed, and some preliminary results are presented.

  16. Interstellar rendezvous missions employing fission propulsion systems

    International Nuclear Information System (INIS)

    Lenard, Roger X.; Lipinski, Ronald J.

    2000-01-01

    There has been a conventionally held nostrum that fission system specific power and energy content is insufficient to provide the requisite high accelerations and velocities to enable interstellar rendezvous missions within a reasonable fraction of a human lifetime. As a consequence, all forms of alternative mechanisms that are not yet, and may never be technologically feasible, have been proposed, including laser light sails, fusion and antimatter propulsion systems. In previous efforts, [Lenard and Lipinski, 1999] the authors developed an architecture that employs fission power to propel two different concepts: one, an unmanned probe, the other a crewed vehicle to Alpha Centauri within mission times of 47 to 60 years. The first portion of this paper discusses employing a variant of the ''Forward Resupply Runway'' utilizing fission systems to enable both high accelerations and high final velocities necessary for this type of travel. The authors argue that such an architecture, while expensive, is considerably less expensive and technologically risky than other technologically advanced concepts, and, further, provides the ability to explore near-Earth stellar systems out to distances of 8 light years or so. This enables the ability to establish independent human societies which can later expand the domain of human exploration in roughly eight light-year increments even presuming that no further physics or technology breakthroughs or advances occur. In the second portion of the paper, a technology requirement assessment is performed. The authors argue that reasonable to extensive extensions to known technology could enable this revolutionary capability

  17. Hybrid fission-fusion nuclear reactors

    International Nuclear Information System (INIS)

    Zucchetti, Massimo

    2011-01-01

    A fusion-fission hybrid could contribute to all components of nuclear power - fuel supply, electricity production, and waste management. The idea of the fusion-fission hybrid is many decades old. Several ideas, both new and revisited, have been investigated by hybrid proponents. These ideas appear to have attractive features, but they require various levels of advances in plasma science and fusion and nuclear technology. As a first step towards the development of hybrid reactors, fusion neutron sources can be considered as an option. Compact high-field tokamaks can be a candidate for being the neutron source in a fission-fusion hybrid, essentially due to their design characteristics, such as compact dimensions, high magnetic field, flexibility of operation. This study presents the development of a tokamak neutron source for a material testing facility using an Ignitor-based concept. The computed values show the potential of this neutron-rich device for fusion materials testing. Some full-power months of operation are sufficient to obtain relevant radiation damage values in terms of dpa. (Author)

  18. Considerations in modeling fission gas release during normal operation

    International Nuclear Information System (INIS)

    Rumble, E.T.; Lim, E.Y.; Stuart, R.G.

    1977-01-01

    The EPRI LWR fuel rod modeling code evaluation program analyzed seven fuel rods with experimental fission gas release data. In these cases, rod-averged burnups are less than 20,000 MWD/MTM, while the fission gas release fractions range roughly from 2 to 27%. Code results demonstrate the complexities in calculating fission gas release in certain operating regimes. Beyond this work, the behavior of a pre-pressurized PWR rod is simulated to average burnups of 40,000 MWD/MTM using GAPCON-THERMAL-2. Analysis of the sensitivity of fission gas release to power histories and release correlations indicate the strong impact that LMFBR type release correlations induce at high burnup. 15 refs

  19. Isotopic composition of fission gases in LWR fuel

    International Nuclear Information System (INIS)

    Jonsson, T.

    2000-01-01

    Many fuel rods from power reactors and test reactors have been punctured during past years for determination of fission gas release. In many cases the released gas was also analysed by mass spectrometry. The isotopic composition shows systematic variations between different rods, which are much larger than the uncertainties in the analysis. This paper discusses some possibilities and problems with use of the isotopic composition to decide from which part of the fuel the gas was released. In high burnup fuel from thermal reactors loaded with uranium fuel a significant part of the fissions occur in plutonium isotopes. The ratio Xe/Kr generated in the fuel is strongly dependent on the fissioning species. In addition, the isotopic composition of Kr and Xe shows a well detectable difference between fissions in different fissile nuclides. (author)

  20. Development of fission Mo-99 production technology

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Ho; Choung, W. M.; Lee, K. I. and others

    2001-05-01

    This R and D project is planed to supply domestic demands of Mo-99 through fission route, and consequently this project will be expected to rise up utilization of HANARO and KAERI's capability for marketing extension into domestic and oversea radiopharmaceutical market. HEU and LEU target types are decided and designed for fission Mo-99 production in domestic. Experimental study of target fabrication technology was performed and developed processing equipments. And conceptual design of target loading/unloading in/from HANARO device are performed. Tracer test of Mo-99 separation and purification process was performed, test results reach to Mo-99 recovery yield above 80% and decontamination factor above 1600. Combined Mo-99 separation and purification process was decided for hot test scheduled from next year, and performance test was performed. Conceptual design for modification of existing hot cell for fission Mo-99 production facility was performed and will be used for detail design. Assumption for the comparison of LEU and HEU target in fission Mo-99 production process were suggested and compared of merits and demerits in view of fabrication technology and economy feasibility.

  1. Development of fission Mo-99 production technology

    International Nuclear Information System (INIS)

    Park, Jin Ho; Choung, W. M.; Lee, K. I. and others

    2001-05-01

    This R and D project is planed to supply domestic demands of Mo-99 through fission route, and consequently this project will be expected to rise up utilization of HANARO and KAERI's capability for marketing extension into domestic and oversea radiopharmaceutical market. HEU and LEU target types are decided and designed for fission Mo-99 production in domestic. Experimental study of target fabrication technology was performed and developed processing equipments. And conceptual design of target loading/unloading in/from HANARO device are performed. Tracer test of Mo-99 separation and purification process was performed, test results reach to Mo-99 recovery yield above 80% and decontamination factor above 1600. Combined Mo-99 separation and purification process was decided for hot test scheduled from next year, and performance test was performed. Conceptual design for modification of existing hot cell for fission Mo-99 production facility was performed and will be used for detail design. Assumption for the comparison of LEU and HEU target in fission Mo-99 production process were suggested and compared of merits and demerits in view of fabrication technology and economy feasibility

  2. Tip model of cold fission

    International Nuclear Information System (INIS)

    Goennenwein, F.; Boersig, B.

    1991-01-01

    Cold fission is defined to be the limiting case of nuclear fission where virtually all of the available energy is converted into the total kinetic energy of the fragments. The fragments have, therefore, to be born in or at least close to their respective ground states. Starting from the viewpoint that cold fission corresponds to most compact scission configurations, energy constraints have been exploited to calculate minimum tip distances between the two nascent fragments in binary fission. Crucial input parameters to this tip model of cold fission are the ground-state deformations of fragment nuclei. It is shown that the minimum tip distances being compatible with energy conservation vary strongly with both the mass and charge fragmentation of the fission prone nucleus. The tip distances refer to nuclei with equivalent sharp surfaces. In keeping with the size of the surface width of leptodermous nuclei, only configurations where the tip distances are smaller than a few fm may be considered as valid scission configurations. From a comparison with experimental data on cold fission this critical tip distance appears to be 3.0 fm for the model parameters chosen. Whenever the model calculation yields tip distances being smaller than the critical value, a necessary condition for attaining cold fission is considered to be fulfilled. It is shown that this criterion allows to understand in fair agreement with experiment which mass fragmentations are susceptible to lead to cold fission and which fragment-charge divisions are the most favored in each isobaric mass chain. Being based merely on energy arguments, the model cannot aim at predicting fragment yields in cold fission. However, the tip model proposed appears well suited to delineate the phase space where cold fission phenomena may come into sight. (orig.)

  3. Post-scission fission theory: Neutron emission in fission

    International Nuclear Information System (INIS)

    Madland, D.G.

    1997-01-01

    A survey of theoretical representations of two of the observables in neutron emission in fission is given, namely, the prompt fission neutron spectrum N (E) and the average prompt neutron multiplicity bar ν p . Early representations of the two observables are presented and their deficiencies are discussed. This is followed by summaries and examples of recent theoretical models for the calculation of these quantities. Emphasis is placed upon the predictability and accuracy of the recent models. In particular, the dependencies of N (E) and bar ν p upon the fissioning nucleus and its excitation energy are treated. Recent work in the calculation of the prompt fission neutron spectrum matrix N (E, E n ), where E n is the energy of the neutron inducing fission, is then discussed. Concluding remarks address the current status of our ability to calculate these observables with confidence, the direction of future theoretical efforts, and limitations to current (and future) approaches

  4. 60 years controlled nuclear fission: CP-1

    International Nuclear Information System (INIS)

    Anon.

    2002-01-01

    On December 2, 1942, the Chicago Pile 1 (CP-1) went critical for the first time. In this way, the scientists and engineers involved in the project under the leadership of Enrico Fermi succeeded in demonstrating that a self-sustaining nuclear reaction with nuclear fission processes was technically feasible. Only four years after the discovery and proof of nuclear fission by Otto Hahn, Fritz Strassmann, and Lise Meitner, the experiment consisting of graphite blocks as the moderator and uranium dioxide pellets as the fuel, as well as instrumentation and control devices, had been set up in the former squash court of the field and track stadium of the University of Chicago. Precisely at 3.36 a.m. Chicago time, after control rods had been withdrawn, the instruments showed the chain reaction by the neutron flux they indicated. An important cornerstone in the use of nuclear power had thus been laid. (orig.)

  5. Monte-Carlo Generation of Time Evolving Fission Chains

    Energy Technology Data Exchange (ETDEWEB)

    Verbeke, Jerome M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kim, Kenneth S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Prasad, Manoj K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Snyderman, Neal J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-08-01

    About a decade ago, a computer code was written to model neutrons from their “birth” to their final “death” in thermal neutron detectors (3He tubes): SrcSim had enough physics to track the neutrons in multiplying systems, appropriately increasing and decreasing the neutron population as they interacted by absorption, fission and leakage. The theory behind the algorithms assumed that all neutrons produced in a fission chain were all produced simultaneously, and then diffused to the neutron detectors. For cases where the diffusion times are long compared to the fission chains, SrcSim is very successful. Indeed, it works extraordinarily well for thermal neutron detectors and bare objects, because it takes tens of microseconds for fission neutrons to slow down to thermal energies, where they can be detected. Microseconds are a very long time compared to the lengths of the fission chains. However, this inherent assumption in the theory prevents its use to cases where either the fission chains are long compared to the neutron diffusion times (water-cooled nuclear reactors, or heavily moderated object, where the theory starts failing), or the fission neutrons can be detected shortly after they were produced (fast neutron detectors). For these cases, a new code needs to be written, where the underlying assumption is not made. The purpose of this report is to develop an algorithm to generate the arrival times of neutrons in fast neutron detectors, starting from a neutron source such as a spontaneous fission source (252Cf) or a multiplying source (Pu). This code will be an extension of SrcSim to cases where correlations between neutrons in the detectors are on the same or shorter time scales as the fission chains themselves.

  6. Nuclear power plants and the environment

    Energy Technology Data Exchange (ETDEWEB)

    Barabas, K [Ceskoslovenska Komise pro Atomovou Energii, Prague

    1978-05-01

    The environmental impacts are compared of conventional coal-fired and oil-fired power plants and of nuclear power plants. The values are compared of SO/sub 2/, NO/sub 2/, ash and soot emissions with /sup 133/Xe and /sup 85/Kr fission products release and the requirement for air for diluting these emissions in the atmosphere is assessed. Also compared are thermal pollution from an oil-fired power plant and from PWR and fast reactor power plants. The conclusion is arrived at that nuclear energy can solve the problem of increasing demand for electric and heat power while reducing negative environmental impacts.

  7. Nuclear power plants and the environment

    International Nuclear Information System (INIS)

    Barabas, K.

    1978-01-01

    The environmental impacts are compared of conventional coal-fired and oil-fired power plants and of nuclear power plants. The values are compared of SO 2 , NO 2 , ash and soot emmisions with 133 Xe and 85 Kr fission products release and the requirement for air for diluting these emissions in the atmosphere is assessed. Also compared are thermal pollution from an oil-fired power plant and from PWR and fast reactor power plants. The conclusion is arrived at that nuclear energy can solve the problem of increasing demand for electric and heat power while reducing negative environmental impacts. (O.K.)

  8. A low power 20 GHz comparator in 90 nm COMS technology

    Science.gov (United States)

    Kai, Tang; Qiao, Meng; Zhigong, Wang; Ting, Guo

    2014-05-01

    A low power 20 GHz CMOS dynamic latched regeneration comparator for ultra-high-speed, low-power analog-to-digital converters (ADCs) is proposed. The time constant in both the tracking and regeneration phases of the latch are analyzed based on the small signal model. A dynamic source-common logic (SCL) topology is adopted in the master-slave latch to increase the tracking and regeneration speeds. Implemented in 90 nm CMOS technology, this comparator only occupies a die area of 65 × 150 μm2 with a power dissipation of 14 mW from a 1.2 V power supply. The measurement results show that the comparator can work up to 20 GHz. Operating with an input frequency of 1 GHz, the circuit can oversample up to 20 Giga-sampling-per-second (GSps) with 5 bits resolution; while operating at Nyquist, the comparator can sample up to 20 GSps with 4 bits resolution. The comparator has been successfully used in a 20 GSps flash ADC and the circuit can be also used in other high speed applications.

  9. Comparative study of popular objective functions for damping power system oscillations in multimachine system.

    Science.gov (United States)

    Islam, Naz Niamul; Hannan, M A; Shareef, Hussain; Mohamed, Azah; Salam, M A

    2014-01-01

    Power oscillation damping controller is designed in linearized model with heuristic optimization techniques. Selection of the objective function is very crucial for damping controller design by optimization algorithms. In this research, comparative analysis has been carried out to evaluate the effectiveness of popular objective functions used in power system oscillation damping. Two-stage lead-lag damping controller by means of power system stabilizers is optimized using differential search algorithm for different objective functions. Linearized model simulations are performed to compare the dominant mode's performance and then the nonlinear model is continued to evaluate the damping performance over power system oscillations. All the simulations are conducted in two-area four-machine power system to bring a detailed analysis. Investigated results proved that multiobjective D-shaped function is an effective objective function in terms of moving unstable and lightly damped electromechanical modes into stable region. Thus, D-shape function ultimately improves overall system damping and concurrently enhances power system reliability.

  10. Phase 1 space fission propulsion system design considerations

    International Nuclear Information System (INIS)

    Houts, Mike; Van Dyke, Melissa; Godfroy, Tom; Pedersen, Kevin; Martin, James; Dickens, Ricky; Salvail, Pat; Hrbud, Ivana; Carter, Robert

    2002-01-01

    Fission technology can enable rapid, affordable access to any point in the solar system. If fission propulsion systems are to be developed to their full potential; however, near-term customers must be identified and initial fission systems successfully developed, launched, and operated. Studies conducted in fiscal year 2001 (IISTP, 2001) show that fission electric propulsion (FEP) systems operating at 80 kWe or above could enhance or enable numerous robotic outer solar system missions of interest. At these power levels it is possible to develop safe, affordable systems that meet mission performance requirements. In selecting the system design to pursue, seven evaluation criteria were identified: safety, reliability, testability, specific mass, cost, schedule, and programmatic risk. A top-level comparison of three potential concepts was performed: an SP-100 based pumped liquid lithium system, a direct gas cooled system, and a heatpipe cooled system. For power levels up to at least 500 kWt (enabling electric power levels of 125-175 kWe, given 25-35% power conversion efficiency) the heatpipe system has advantages related to several criteria and is competitive with respect to all. Hardware-based research and development has further increased confidence in the heatpipe approach. Successful development and utilization of a 'Phase 1' fission electric propulsion system will enable advanced Phase 2 and Phase 3 systems capable of providing rapid, affordable access to any point in the solar system

  11. Comparative analysis of print media coverage of nuclear power and coal issues

    International Nuclear Information System (INIS)

    Nealey, S.M.; Rankin, W.L.; Montano, D.E.

    1978-10-01

    Nuclear power has been a more important topic than has coal for the print media, and has received somewhat different treatment. Compared to the number of coal articles, almost twice as many nuclear power articles were printed from 1972 through 1976. Also, while the number of nuclear power articles increased somewhat steadily from 1972 through 1976, the number of coal articles peaked in 1974 and has decreased since. The newspapers sampled gave more prominence to nuclear articles in terms of article type and article location. Also, nuclear articles were more often issue-oriented compared to coal articles. Coal articles were most often about coal mining, labor force concerns, and regulations controls. Nuclear power articles, on the other hand, were mostly about reactor operation. The main issues discussed in the coal articles pertained most to political decisions affecting coal use, to strikes, and to health and safety. The main nuclear issues pertained to economics, to health and safety, and to political decisions. Newspapers handled nuclear power articles in a more polarized manner compared to coal articles which were handled in a more neutral manner. Magazine articles were significantly more antinuclear than anticoal. Some qualifications about these conclusions are included

  12. High flux transmutation of fission products and actinides

    International Nuclear Information System (INIS)

    Gerasimov, A.; Kiselev, G.; Myrtsymova, L.

    2001-01-01

    Long-lived fission products and minor actinides accumulated in spent nuclear fuel of power reactors comprise the major part of high level radwaste. Their incineration is important from the point of view of radwaste management. Transmutation of these nuclides by means of neutron irradiation can be performed either in conventional nuclear reactors, or in specialized transmutation reactors, or in ADS facilities with subcritical reactor and neutron source with application of proton accelerator. Different types of transmutation nuclear facilities can be used in order to insure optimal incineration conditions for radwaste. The choice of facility type for optimal transmutation should be based on the fundamental data in the physics of nuclide transformations. Transmutation of minor actinides leads to the increase of radiotoxicity during irradiation. It takes significant time compared to the lifetime of reactor facility to achieve equilibrium without effective transmutation. High flux nuclear facilities allow to minimize these draw-backs of conventional facilities with both thermal and fast neutron spectrum. They provide fast approach to equilibrium and low level of equilibrium mass and radiotoxicity of transmuted actinides. High flux facilities are advantageous also for transmutation of long-lived fission products as they provide short incineration time

  13. Influence of fission product transport on delayed neutron precursors and decay heat sources in LMFBR accidents

    International Nuclear Information System (INIS)

    Apperson, C.E. Jr.

    1981-01-01

    A method is presented for studying the influence of fission product transpot on delayed neutron precursors and decay heat sources during Liquid Metal Fast Breeder Reactor (LMFBR) unprotected accidents. The model represents the LMFBR core as a closed homogeneous cell. Thermodynamic phase equilibrium theory is used to predict fission product mobility. Reactor kinetics behavior is analyzed by an extension of point kinetics theory. Group dependent delayed neutron precursor and decay heat source retention factors, which represent the fraction of each group retained in the fuel, are developed to link the kinetics and thermodynamics analysis. Application of the method to a highly simplified model of an unprotected loss-of-flow accident shows a time delay on the order of 10 ms is introduced in the predisassembly power history if fission product motion is considered when compared to the traditional transient solution. The post-transient influence of fission product transport calculated by the present model is a 24 percent reduction in the decay heat level in the fuel material which is similar to traditional approximations. Isotopes of the noble gases, Kr and Xe, and the elements I and Br are shown to be very mobile and are responsible for a major part of the observed effects. Isotopes of the elements Cs, Se, Rb, and Te were found to be moderately mobile and contribute to a lesser extent to the observed phenomena. These results obtained from the application of the described model confirm the initial hypothesis that sufficient fission product transport can occur to influence a transient. For these reasons, it is concluded that extension of this model into a multi-cell transient analysis code is warranted

  14. An Integrated Power-Efficient Active Rectifier With Offset-Controlled High Speed Comparators for Inductively Powered Applications

    Science.gov (United States)

    Lee, Hyung-Min; Ghovanloo, Maysam

    2011-01-01

    We present an active full-wave rectifier with offset-controlled high speed comparators in standard CMOS that provides high power conversion efficiency (PCE) in high frequency (HF) range for inductively powered devices. This rectifier provides much lower dropout voltage and far better PCE compared to the passive on-chip or off-chip rectifiers. The built-in offset-control functions in the comparators compensate for both turn-on and turn-off delays in the main rectifying switches, thus maximizing the forward current delivered to the load and minimizing the back current to improve the PCE. We have fabricated this active rectifier in a 0.5-μm 3M2P standard CMOS process, occupying 0.18 mm2 of chip area. With 3.8 V peak ac input at 13.56 MHz, the rectifier provides 3.12 V dc output to a 500 Ω load, resulting in the PCE of 80.2%, which is the highest measured at this frequency. In addition, overvoltage protection (OVP) as safety measure and built-in back telemetry capabilities have been incorporated in our design using detuning and load shift keying (LSK) techniques, respectively, and tested. PMID:22174666

  15. Sensitivity and uncertainty analysis for fission product decay heat calculations

    International Nuclear Information System (INIS)

    Rebah, J.; Lee, Y.K.; Nimal, J.C.; Nimal, B.; Luneville, L.; Duchemin, B.

    1994-01-01

    The calculated uncertainty in decay heat due to the uncertainty in basic nuclear data given in the CEA86 Library, is presented. Uncertainties in summation calculation arise from several sources: fission product yields, half-lives and average decay energies. The correlation between basic data is taken into account. The uncertainty analysis were obtained for thermal-neutron-induced fission of U235 and Pu239 in the case of burst fission and irradiation time. The calculated decay heat in this study is compared with experimental results and with new calculation using the JEF2 Library. (from authors) 6 figs., 19 refs

  16. Fission fragment driven neutron source

    Science.gov (United States)

    Miller, Lowell G.; Young, Robert C.; Brugger, Robert M.

    1976-01-01

    Fissionable uranium formed into a foil is bombarded with thermal neutrons in the presence of deuterium-tritium gas. The resulting fission fragments impart energy to accelerate deuterium and tritium particles which in turn provide approximately 14 MeV neutrons by the reactions t(d,n).sup.4 He and d(t,n).sup.4 He.

  17. Neutron multiplicity of fission fragments

    Energy Technology Data Exchange (ETDEWEB)

    Abdelrahman, Y S [Physics department, mu` rah university Al-Karak, (Jordan)

    1995-10-01

    The total average neutron multiplicity of the fission fragments produced by the spontaneous fission of {sup 248} Cm has been measured. This measurement has been done by using a new experimental technique. This technique mainly depends on {gamma}-{gamma} coincidence using a very high resolution high purity germanium (HPGe) detector. 2 figs.

  18. Fission throughout the periodic table

    International Nuclear Information System (INIS)

    Moretto, L.G.; Wozniak, G.J.

    1989-04-01

    The dualistic view of fission and evaporation as two distinct compound nucleus processes is substituted with a unified view in which fission, complex fragment emission, and light particle evaporation are seen as different aspects of a single process. 47 refs., 22 figs

  19. Power reactors and sub-critical blanket systems with lead and lead-bismuth as coolant and/or target material. Utilization and transmutation of actinides and long lived fission products

    International Nuclear Information System (INIS)

    2003-05-01

    High level radioactive waste disposal is an issue of great importance in the discussion of the sustainability of nuclear power generation. The main contributors to the high radioactivity are the fission products and the minor actinides. The long lived fission products and minor actinides set severe demands on the arrangements for safe waste disposal. Fast reactors and accelerator driven systems (ADS) are under development in Member States to reduce the long term hazard of spent fuel and radioactive waste, taking advantage of their incineration and transmutation capability. Important R and D programmes are being undertaken in many Member States to substantiate this option and advance the basic knowledge in this innovative area of nuclear energy development. The conceptual design of the lead cooled fast reactor concept BREST-OD-300, as well as various other conceptual designs of lead/lead-bismuth cooled fast reactors have been developed to meet enhanced safety and non-proliferation requirements, aiming at both energy production and transmutation of nuclear waste. Some R and D studies indicate that the use of lead and lead-bismuth coolant has some advantages in comparison with existing sodium cooled fast reactor systems, e.g.: simplified design of fast reactor core and BOP, enhanced inherent safety, and easier radwaste management in related fuel cycles. Moreover, various ADS conceptual designs with lead and lead-bismuth as target material and coolant also have been pursued. The results to date are encouraging, indicating that the ADS has the potential to offer an option for meeting the challenges of the back end fuel cycle. During the last decade, there have been substantial advances in several countries with their own R and D programme in the fields of lead/lead-bismuth cooled critical and sub-critical concepts. coolant technology, and experimental validation. In this context, international exchange of information and experience, as well as international

  20. Shift in Comparative Advantage, Dynamic Market and Purchasing Power Parity in the East Asia

    OpenAIRE

    Widodo,Tri

    2008-01-01

    The regional economic integrations, bilateral trade agreements (BTAs), and otherinternational strategic alliances have affected countries' dynamic comparative advantagesand specialization. Whether there are systematic changes in the comparative advantageand specialization of trade in the East-Asian countries has been a crucial issue for thefuture development of the East-Asian economic integration. One of the most importantissues in the international trade is exchange rate. Purchasing Power Pa...

  1. Progress in fission product nuclear data

    International Nuclear Information System (INIS)

    Lammer, M.

    1984-09-01

    This is the tenth issue of a report series on Fission Product Data, which informs us about all the activities in this field, which are planned, ongoing, or have recently been completed. The types of activities included are measurements, compilations and evaluations of: fission product yields (neutron induced and spontaneous fission), neutron reaction cross sections of fission products, data related to the radioactive decay of fission products, delayed neutron data of fission products, lumped fission product data (decay heat, absorption, etc.). There is also a section with recent references relative to fission product nuclear data

  2. Mechanisms of fission neutron emission

    International Nuclear Information System (INIS)

    Maerten, H.

    1991-01-01

    The time evolution in fission is the starting point for discussing not only the main mechanism of fission neutron emission, the evaporation from fully accelerated fragments, but also possible secondary ones connected with dynamical features of nuclear fission. ''Asymptotic'' conditions as relevant for describing the particle release from highly excited, rapidly moving fragments are defined. Corresponding statistical model approaches to fission neutron emission, based on the adequate consideration of the intricate fragment occurrence probability, reproduce most of the experimental data. The remarkable influence of fission modes on neutron observables is analyzed in the framework of a macroscopic-microscopic scission point model consistent with energy conservation. Finally, chances and deficiencies for solving the mechanism puzzle are summarized. (author). 87 refs, 21 figs

  3. Singlet exciton fission in polycrystalline pentacene: from photophysics toward devices.

    Science.gov (United States)

    Wilson, Mark W B; Rao, Akshay; Ehrler, Bruno; Friend, Richard H

    2013-06-18

    generated via singlet fission in pentacene can be dissociated at an interface with a suitable electron acceptor, such as fullerenes and infrared-absorbing inorganic semiconducting quantum dots. We highlight our recent reports of a pentacene/PbSe hybrid solar cell with a power conversion efficiency of 4.7% and of a pentacene/PbSe/amorphous silicon photovoltaic device. Although substantive challenges remain, both to better our understanding of the mechanism of singlet exciton fission and to optimize device performance, this realization of a solar cell where photocurrent is simultaneously contributed from a blue-absorbing fission-capable material and an infrared-absorbing conventional cell is an important step towards a dual-bandgap, single-junction, fission-enhanced photovoltaic device, which could one day surpass the Shockley-Queisser limit.

  4. Isotopic signature and nano-texture of cesium-rich micro-particles: Release of uranium and fission products from the Fukushima Daiichi Nuclear Power Plant.

    Science.gov (United States)

    Imoto, Junpei; Ochiai, Asumi; Furuki, Genki; Suetake, Mizuki; Ikehara, Ryohei; Horie, Kenji; Takehara, Mami; Yamasaki, Shinya; Nanba, Kenji; Ohnuki, Toshihiko; Law, Gareth T W; Grambow, Bernd; Ewing, Rodney C; Utsunomiya, Satoshi

    2017-07-14

    Highly radioactive cesium-rich microparticles (CsMPs) released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) provide nano-scale chemical fingerprints of the 2011 tragedy. U, Cs, Ba, Rb, K, and Ca isotopic ratios were determined on three CsMPs (3.79-780 Bq) collected within ~10 km from the FDNPP to determine the CsMPs' origin and mechanism of formation. Apart from crystalline Fe-pollucite, CsFeSi 2 O 6  · nH 2 O, CsMPs are comprised mainly of Zn-Fe-oxide nanoparticles in a SiO 2 glass matrix (up to ~30 wt% of Cs and ~1 wt% of U mainly associated with Zn-Fe-oxide). The 235 U/ 238 U values in two CsMPs: 0.030 (±0.005) and 0.029 (±0.003), are consistent with that of enriched nuclear fuel. The values are higher than the average burnup estimated by the ORIGEN code and lower than non-irradiated fuel, suggesting non-uniform volatilization of U from melted fuels with different levels of burnup, followed by sorption onto Zn-Fe-oxides. The nano-scale texture and isotopic analyses provide a partial record of the chemical reactions that occurred in the fuel during meltdown. Also, the CsMPs were an important medium of transport for the released radionuclides in a respirable form.

  5. Fifty years with nuclear fission

    International Nuclear Information System (INIS)

    Behrens, J.W.; Carlson, A.D.

    1989-01-01

    The news of the discovery of nuclear fission, by Otto Hahn and Fritz Strassmann in Germany, was brought to the United States by Niels Bohr in January 1939. Since its discovery, the United States, and the world for that matter, has never been the same. It therefore seemed appropriate to acknowledge the fifieth anniversary of its discovery by holding a topical meeting entitled, ''Fifty Years with Nuclear Fission,'' in the United States during the year 1989. The objective of the meeting was to bring together pioneers of the nuclear industry and other scientists and engineers to report on reminiscences of the past and on the more recent development in fission science and technology. The conference highlighted the early pioneers of the nuclear industry by dedicated a full day (April 26), consisting of two plenary sessions, at the National Academy of Sciences (NAS) in Washington, DC. More recent developments in fission science and technology in addition to historical reflections were topics for two fully days of sessions (April 27 and 28) at the main site of the NIST in Gaithersburg, Maryland. The wide range of topics covered in this Volume 1 by this topical meeting included plenary invited, and contributed sessions entitled: Preclude to the First Chain Reaction -- 1932 to 1942; Early Fission Research -- Nuclear Structure and Spontaneous Fission; 50 Years of Fission, Science, and Technology; Nuclear Reactors, Secure Energy for the Future; Reactors 1; Fission Science 1; Safeguards and Space Applications; Fission Data; Nuclear Fission -- Its Various Aspects; Theory and Experiments in Support of Theory; Reactors and Safeguards; and General Research, Instrumentation, and By-Product. The individual papers have been cataloged separately

  6. Modelling animal group fission using social network dynamics.

    Directory of Open Access Journals (Sweden)

    Cédric Sueur

    Full Text Available Group life involves both advantages and disadvantages, meaning that individuals have to compromise between their nutritional needs and their social links. When a compromise is impossible, the group splits in order to reduce conflict of interests and favour positive social interactions between its members. In this study we built a dynamic model of social networks to represent a succession of temporary fissions involving a change in social relations that could potentially lead to irreversible group fission (i.e. no more group fusion. This is the first study that assesses how a social network changes according to group fission-fusion dynamics. We built a model that was based on different parameters: the group size, the influence of nutritional needs compared to social needs, and the changes in the social network after a temporary fission. The results obtained from this theoretical data indicate how the percentage of social relation transfer, the number of individuals and the relative importance of nutritional requirements and social links influence the average number of days before irreversible fission occurs. The greater the nutritional needs and the higher the transfer of social relations during temporary fission, the fewer days will be observed before an irreversible fission. It is crucial to bridge the gap between the individual and the population level if we hope to understand how simple, local interactions may drive ecological systems.

  7. A Note on Comparing the Power of Test Statistics at Low Significance Levels.

    Science.gov (United States)

    Morris, Nathan; Elston, Robert

    2011-01-01

    It is an obvious fact that the power of a test statistic is dependent upon the significance (alpha) level at which the test is performed. It is perhaps a less obvious fact that the relative performance of two statistics in terms of power is also a function of the alpha level. Through numerous personal discussions, we have noted that even some competent statisticians have the mistaken intuition that relative power comparisons at traditional levels such as α = 0.05 will be roughly similar to relative power comparisons at very low levels, such as the level α = 5 × 10 -8 , which is commonly used in genome-wide association studies. In this brief note, we demonstrate that this notion is in fact quite wrong, especially with respect to comparing tests with differing degrees of freedom. In fact, at very low alpha levels the cost of additional degrees of freedom is often comparatively low. Thus we recommend that statisticians exercise caution when interpreting the results of power comparison studies which use alpha levels that will not be used in practice.

  8. Power of tests for comparing trend curves with application to national immunization survey (NIS).

    Science.gov (United States)

    Zhao, Zhen

    2011-02-28

    To develop statistical tests for comparing trend curves of study outcomes between two socio-demographic strata across consecutive time points, and compare statistical power of the proposed tests under different trend curves data, three statistical tests were proposed. For large sample size with independent normal assumption among strata and across consecutive time points, the Z and Chi-square test statistics were developed, which are functions of outcome estimates and the standard errors at each of the study time points for the two strata. For small sample size with independent normal assumption, the F-test statistic was generated, which is a function of sample size of the two strata and estimated parameters across study period. If two trend curves are approximately parallel, the power of Z-test is consistently higher than that of both Chi-square and F-test. If two trend curves cross at low interaction, the power of Z-test is higher than or equal to the power of both Chi-square and F-test; however, at high interaction, the powers of Chi-square and F-test are higher than that of Z-test. The measurement of interaction of two trend curves was defined. These tests were applied to the comparison of trend curves of vaccination coverage estimates of standard vaccine series with National Immunization Survey (NIS) 2000-2007 data. Copyright © 2011 John Wiley & Sons, Ltd.

  9. Microscopic theory of nuclear fission: a review

    Science.gov (United States)

    Schunck, N.; Robledo, L. M.

    2016-11-01

    This article reviews how nuclear fission is described within nuclear density functional theory. A distinction should be made between spontaneous fission, where half-lives are the main observables and quantum tunnelling the essential concept, and induced fission, where the focus is on fragment properties and explicitly time-dependent approaches are often invoked. Overall, the cornerstone of the density functional theory approach to fission is the energy density functional formalism. The basic tenets of this method, including some well-known tools such as the Hartree-Fock-Bogoliubov (HFB) theory, effective two-body nuclear potentials such as the Skyrme and Gogny force, finite-temperature extensions and beyond mean-field corrections, are presented succinctly. The energy density functional approach is often combined with the hypothesis that the time-scale of the large amplitude collective motion driving the system to fission is slow compared to typical time-scales of nucleons inside the nucleus. In practice, this hypothesis of adiabaticity is implemented by introducing (a few) collective variables and mapping out the many-body Schrödinger equation into a collective Schrödinger-like equation for the nuclear wave-packet. The region of the collective space where the system transitions from one nucleus to two (or more) fragments defines what are called the scission configurations. The inertia tensor that enters the kinetic energy term of the collective Schrödinger-like equation is one of the most essential ingredients of the theory, since it includes the response of the system to small changes in the collective variables. For this reason, the two main approximations used to compute this inertia tensor, the adiabatic time-dependent HFB and the generator coordinate method, are presented in detail, both in their general formulation and in their most common approximations. The collective inertia tensor enters also the Wentzel-Kramers-Brillouin (WKB) formula used to extract

  10. Nuclear Power and Environment Comparative Assessment of Environmental and Health Impacts of Electricity Generating Systems

    International Nuclear Information System (INIS)

    Rashed, S.M.

    1999-01-01

    This paper deals with comparative assessment of the environmental and health impacts of nuclear and other electricity generation systems. The study including normal operations and accidents in full energy chain analysis. The comparison of the environmental impacts arising from the waste management cycles associated with non emission waste are also discussed. Nuclear Power while economically feasible and meeting 17% of the world,s demand for electricity is almost free of the air polluting gases that threaten the global climate. Comparing nuclear power with other sources for electricity generation in terms of their associated environmental releases of pollutant such as SO 2 , NOX, CO 2 , CH 4 and radioisotopes, taking into account the full fuel chains chains of supply option, nuclear power will help to reduce environmental degradation due to electricity generation activities. In view of CO 2 emission, the ranking order commences with hydro, followed by nuclear, wind and photovoltaic Power Plants. CO 2 emissions from a nuclear power plant are by two orders of magnitude lower than those of fossil fueled power plants. A consequent risk comparison between different energy sources has to include al phases of the whole energy cycle. Coal mines accidents have resulted in several 1000 acute deaths over the years. Later fatalities have never been estimated. Then came hydropower, also resulting in many catastrophes and losses of human lives. Followed oil and gas energy industry, its tribute in acute fatalities is expressed in more than 1000 life lost. No estimate is available concerning later fatalities. latest in the list is commercial nuclear energy, badly illustrated by the Chernobyl accident resulting officially in 31 acute fatalities, 145 latent fatalities, and 135000 evacuated individuals. The paper offers some findings and conclusions on the role of nuclear power in protecting the global environment

  11. Comparing the market for nuclear power in Alberta and Saskatchewan - draft paper

    Energy Technology Data Exchange (ETDEWEB)

    Bratt, D. [Dept. of Policy Studies, Mount Royal College, Calgary, Alberta (Canada)], E-mail: dbratt@mtroyal.ca

    2009-07-01

    This paper compares the markets for nuclear power in Alberta and Saskatchewan. This is done by comparing the two provincial panels that were released in Spring 2009 (Saskatchewan's Uranium Development Partnership and Alberta's Nuclear Power Expert Panel). Each panels terms of reference, membership, process, analysis, recommendations, and public consultation process are examined. Other variables for comparison include the history of its involvement in the nuclear sector, the political support, and public support. It concludes by arguing that Saskatchewan is a better market for nuclear power and that it is likely that a nuclear reactor will be built in Saskatchewan, but that surplus electricity will also be exported to Alberta. The possibility of building new nuclear power plants in both Alberta and Saskatchewan is increasing. This would not only increase the size of the Canadian nuclear industry it would also geographically expand it. Many non-Westerners see the prairies as a homogenous whole, but there are critical differences between Alberta and Saskatchewan. Analyzing these political and market differences would provide a good predicative power over the ultimate success of the nuclear power initiatives. This paper conducts a detailed comparison of the Alberta Government's Nuclear Power Expert Panel (NPEP) report and the Saskatchewan Government's Uranium Development Partnership (UDP) report. Topics for comparison include the terms of reference, membership, process, analysis, recommendations, and public consultation process. It also examines the history of each province's involvement in the nuclear industry; the level of political support including the positions of the provincial political parties; and the level of public support and knowledge. (author)

  12. Comparing the market for nuclear power in Alberta and Saskatchewan - draft paper

    International Nuclear Information System (INIS)

    Bratt, D.

    2009-01-01

    This paper compares the markets for nuclear power in Alberta and Saskatchewan. This is done by comparing the two provincial panels that were released in Spring 2009 (Saskatchewan's Uranium Development Partnership and Alberta's Nuclear Power Expert Panel). Each panels terms of reference, membership, process, analysis, recommendations, and public consultation process are examined. Other variables for comparison include the history of its involvement in the nuclear sector, the political support, and public support. It concludes by arguing that Saskatchewan is a better market for nuclear power and that it is likely that a nuclear reactor will be built in Saskatchewan, but that surplus electricity will also be exported to Alberta. The possibility of building new nuclear power plants in both Alberta and Saskatchewan is increasing. This would not only increase the size of the Canadian nuclear industry it would also geographically expand it. Many non-Westerners see the prairies as a homogenous whole, but there are critical differences between Alberta and Saskatchewan. Analyzing these political and market differences would provide a good predicative power over the ultimate success of the nuclear power initiatives. This paper conducts a detailed comparison of the Alberta Government's Nuclear Power Expert Panel (NPEP) report and the Saskatchewan Government's Uranium Development Partnership (UDP) report. Topics for comparison include the terms of reference, membership, process, analysis, recommendations, and public consultation process. It also examines the history of each province's involvement in the nuclear industry; the level of political support including the positions of the provincial political parties; and the level of public support and knowledge. (author)

  13. Robust singlet fission in pentacene thin films with tuned charge transfer interactions.

    Science.gov (United States)

    Broch, K; Dieterle, J; Branchi, F; Hestand, N J; Olivier, Y; Tamura, H; Cruz, C; Nichols, V M; Hinderhofer, A; Beljonne, D; Spano, F C; Cerullo, G; Bardeen, C J; Schreiber, F

    2018-03-05

    Singlet fission, the spin-allowed photophysical process converting an excited singlet state into two triplet states, has attracted significant attention for device applications. Research so far has focused mainly on the understanding of singlet fission in pure materials, yet blends offer the promise of a controlled tuning of intermolecular interactions, impacting singlet fission efficiencies. Here we report a study of singlet fission in mixtures of pentacene with weakly interacting spacer molecules. Comparison of experimentally determined stationary optical properties and theoretical calculations indicates a reduction of charge-transfer interactions between pentacene molecules with increasing spacer molecule fraction. Theory predicts that the reduced interactions slow down singlet fission in these blends, but surprisingly we find that singlet fission occurs on a timescale comparable to that in pure crystalline pentacene. We explain the observed robustness of singlet fission in such mixed films by a mechanism of exciton diffusion to hot spots with closer intermolecular spacings.

  14. Fission fragment angular distributions in proton-induced fission of 209Bi (p,f) and 197Au (p,f)

    International Nuclear Information System (INIS)

    Soheily, S.; Noshad, H.; Lamehi-Rashti, M.

    2002-01-01

    The fission fragment angular distributions have been measured for proton-induced fission of 209 B i and 197 A u nuclei using surface barrier detectors at several energies between 25 MeV and 30 MeV. The experimental anisotropies are found to be in agreement with the predictions of the Standard Saddle-Point Statistical Model. The fission cross sections of 209 B i and 197 A u nuclei were also measured and compared with the previous works

  15. How fission was discovered

    International Nuclear Information System (INIS)

    Fluegge, S.

    1989-01-01

    After the great survey of neutron induced radioactivity by Fermi and co-workers, the laboratories in Paris and Berlin-Dahlen tried to disentangle the complex results found in uranium. At that time neutron sources were small, activities low, and equipment very simple. Chemistry beyond uranium still was unknown. Hahn and Meitner believed to have observed three transuranic isomeric chains, a doubtful result even then. Early in 1938, Curie and Savic in Paris found an activity interpreted to be actinium, and Hahn and Meitner another to be radium. Both interpretations seemed impossible from energy considerations. Hahn and Strassmann, therefore, continued this work and succeeded to separate the new activity from radium. There remained no doubt that a barium isotope had been produced, the uranium nucleus splitting in the yet-unknown process we now call fission

  16. MOSFET-like CNFET based logic gate library for low-power application: a comparative study

    International Nuclear Information System (INIS)

    Gowri Sankar, P. A.; Udhayakumar, K.

    2014-01-01

    The next generation of logic gate devices are expected to depend upon radically new technologies mainly due to the increasing difficulties and limitations of existing CMOS technology. MOSFET like CNFETs should ideally be the best devices to work with for high-performance VLSI. This paper presents results of a comprehensive comparative study of MOSFET-like carbon nanotube field effect transistors (CNFETs) technology based logic gate library for high-speed, low-power operation than conventional bulk CMOS libraries. It focuses on comparing four promising logic families namely: complementary-CMOS (C-CMOS), transmission gate (TG), complementary pass logic (CPL) and Domino logic (DL) styles are presented. Based on these logic styles, the proposed library of static and dynamic NAND-NOR logic gates, XOR, multiplexer and full adder functions are implemented efficiently and carefully analyzed with a test bench to measure propagation delay and power dissipation as a function of supply voltage. This analysis provides the right choice of logic style for low-power, high-speed applications. Proposed logic gates libraries are simulated using Synopsys HSPICE based on the standard 32 nm CNFET model. The simulation results demonstrate that, it is best to use C-CMOS logic style gates that are implemented in CNFET technology which are superior in performance compared to other logic styles, because of their low average power-delay-product (PDP). The analysis also demonstrates how the optimum supply voltage varies with logic styles in ultra-low power systems. The robustness of the proposed logic gate library is also compared with conventional and state-art of CMOS logic gate libraries. (semiconductor integrated circuits)

  17. Release of fission products in transients

    International Nuclear Information System (INIS)

    Christensen, H.; Lundqwist, R.

    1979-07-01

    A station for automatic sampling of coolant has been put in operation at the Oskarshamn-1 reactor. The release of 131 J and other fission products in spikes in connection with reactor trips and scheduled shutdowns has been measured. A model developed at General Electric has been used to predict the spike release in Oskarshamn-1 and the predicted values have been compared with experimental values. Literature data of iodine spikes in BWR and PWR have been reviewed. (author)

  18. Fifty years with nuclear fission

    International Nuclear Information System (INIS)

    Behrens, J.W.; Carlson, A.D.

    1989-01-01

    The news of the discovery of nucler fission, by Otto Hahn and Fritz Strassmann in Germany, was brought to the United States by Niels Bohr in January 1939. Since its discovery, the United States, and the world for that matter, has never been the same. It therefore seemed appropriate to acknowledge the fiftieth anniversary of its discovery by holding a topical meeting entitled, ''Fifty years with nuclear fission,'' in the United States during the year 1989. The objective of the meeting was to bring together pioneers of the nuclear industry and other scientists and engineers to report on reminiscences of the past and on the more recent developments in fission science and technology. The conference highlighted the early pioneers of the nuclear industry by dedicating a full day (April 26), consisting of two plenary sessions, at the National Academy of Sciences (NAS) in Washington, DC. More recent developments in fission science and technology in addition to historical reflections were topics for two full days of sessions (April 27 and 28) at the main sites of the NIST in Gaithersburg, Maryland. The wide range of topics covered by Volume 2 of this topical meeting included plenary invited, and contributed sessions entitled, Nuclear fission -- a prospective; reactors II; fission science II; medical and industrial applications by by-products; reactors and safeguards; general research, instrumentation, and by-products; and fission data, astrophysics, and space applications. The individual papers have been cataloged separately

  19. Fusion-fission hybrid reactors

    International Nuclear Information System (INIS)

    Greenspan, E.

    1984-01-01

    This chapter discusses the range of characteristics attainable from hybrid reactor blankets; blanket design considerations; hybrid reactor designs; alternative fuel hybrid reactors; multi-purpose hybrid reactors; and hybrid reactors and the energy economy. Hybrid reactors are driven by a fusion neutron source and include fertile and/or fissile material. The fusion component provides a copious source of fusion neutrons which interact with a subcritical fission component located adjacent to the plasma or pellet chamber. Fissile fuel and/or energy are the main products of hybrid reactors. Topics include high F/M blankets, the fissile (and tritium) breeding ratio, effects of composition on blanket properties, geometrical considerations, power density and first wall loading, variations of blanket properties with irradiation, thermal-hydraulic and mechanical design considerations, safety considerations, tokamak hybrid reactors, tandem-mirror hybrid reactors, inertial confinement hybrid reactors, fusion neutron sources, fissile-fuel and energy production ability, simultaneous production of combustible and fissile fuels, fusion reactors for waste transmutation and fissile breeding, nuclear pumped laser hybrid reactors, Hybrid Fuel Factories (HFFs), and scenarios for hybrid contribution. The appendix offers hybrid reactor fundamentals. Numerous references are provided

  20. Nuclear fission and fission-product spectroscopy: 3. International workshop on nuclear fission and fission-product spectroscopy

    International Nuclear Information System (INIS)

    Goutte, Heloise; Fioni, Gabriele; Faust, Herbert; Goutte, Dominique

    2005-01-01

    The present book contains the proceedings of the third workshop in a series of workshops previously held in Seyssins in 1994 and 1998. The meeting was jointly organized by different divisions of CEA and two major international laboratories. In the opening address, Prof. B. Bigot, the French High Commissioner for Atomic Energy, outlined France's energy policy for the next few decades. He emphasized the continuing progress of nuclear fission in both technical and economic terms, allowing it to contribute to the energy needs of the planet even more in the future than it does today. Such progress implies a very strong link between fundamental and applied research based on experimental and theoretical approaches. The workshop gathered the different nuclear communities studying the fission process, including topics as the following: - nuclear fission experiments, - spectroscopy of neutron rich nuclei, - fission data evaluation, - theoretical aspects of nuclear fission, - and innovative nuclear systems and new facilities. The scientific program was suggested by an International Advisory Committee. About 100 scientists from 13 different countries attended the conference in the friendly working atmosphere of the Castle of Cadarache in the heart of the Provence. The proceedings of the workshop were divided into 11 sections addressing the following subject matters: 1. Cross sections and resonances (5 papers); 2. Fission at higher energies - I (5 papers); 3. Fission: mass and charge yields (4 papers); 4. Light particles and cluster emission (4 papers); 5. Spectroscopy of neutron rich nuclei (5 papers); 6. Resonances, barriers, and fission times (5 papers); 7. Fragment excitation and neutron emission (4 papers); 8. Mass and energy distributions (4 papers); 9. Needs for nuclear data and new facilities - I (4 papers); 10. Angular momenta and fission at higher Energies - II (3 papers); 11. New facilities - II (2 papers). A poster session of 8 presentations completed the workshop

  1. Comparative study of microcontroller controlled four-wire voltage and current source shunt active power filters

    Energy Technology Data Exchange (ETDEWEB)

    Pettersson, S.

    2009-07-01

    During the past two decades, active power filters have increasingly grown their popularity as a viable method for improving electric power quality. The main reasons for this have been the advent of fast self-commutating solid-state devices, the progression of digital technology and the improved sensor technology. Four-wire active power filters provide an efficient solution for improving the quality of supply in grounded three-phase systems or three-phase systems with neutral conductors, which are commonly used for powering residential, office and public buildings. Four-wire active power filters are applicable in compensating current harmonics, reactive power, neutral current and load phase imbalance.This thesis presents a comparative study of microcontroller controlled four-wire voltage and current source shunt active power filters. The study includes two voltage source topologies and a current source topology with two different dc-link energy storage structures, which are compared on the basis of their filtering properties, filtering performance and efficiency. The obtained results are used for determining the suitability of current source technology for four-wire active power filtering and finding the most viable four-wire shunt active power filter topology. One commonly recognized disadvantage of the current source active power filter has always been the bulky dc-link inductor. To reduce the size of the dc-link inductor, an alternative dc-link structure for current source active power filters was introduced in the late 80's. The hybrid energy storage consists of both inductive and capacitive energy storage elements, two diodes and two controllable semiconductor switching devices. Since the capacitive element is used as a main storage unit, the inductance of the dc-link inductor can be considerably reduced. However, the original dc current control method proposed is not able to utilize the full potential of the hybrid energy storage and the inductance

  2. Polarographic determination of Iodide and Iodate, in Solutions Coming from Aerosols in Fission Products Containment Studies in Nuclear Power Stations; Determinacion Polarografica de Especies de Iodo (Ioduro y Iodato) en Soluciones Procedentes de Aerosoles, para Estudios de Contencion de Productos de Fision en Centrales Nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, M.; Ballesteros, O.; Fernandez, M.; Clavero, M.; Gonzalez, A. M. [Ciemat, Madrid (Spain)

    2000-07-01

    A polarographic method is described for the iodine species determination, iodide and iodate in water solutions. the iodate can be determined by differential pulse polarography. Calibration curves and the detection and determination limits have been obtained. Iodides is oxidized to iodate with sodium hypochlorite and the excess of oxidizing agent is destroyed with sodium sulphide. The concentration of iodide is calculated as the difference between the concentration of iodate in the sample before and after the oxidation. As an application, species of iodine in samples coming from the experimental plants GIRS (Gaseous Iodine Removal by Sprays) of Nuclear Fission Department of the CIEMAT, dedicated to fission products containment studies in nuclear power station, were determined. (Author) 10 refs.

  3. Gamma Radiation from Fission Fragments

    International Nuclear Information System (INIS)

    Higbie, Jack

    1969-10-01

    The gamma radiation from the fragments of the thermal neutron fission of 235 U has been investigated, and the preliminary data are presented here with suggestions for further lines of research and some possible interpretations of the data. The data have direct bearing on the fission process and the mode of fragment de-excitation. The parameters measured are the radiation decay curve for the time interval (1 - 7) x 10 -10 sec after fission, the photon yield, the total gamma ray energy yield, and the average photon energy. The last three quantities are measured as a function of the fragment mass

  4. Energy partition in nuclear fission

    International Nuclear Information System (INIS)

    Ruben, A.; Maerten, H.; Seeliger, D.

    1990-01-01

    A scission point model (two spheroid model TSM) including semi-empirical temperature-dependent shell correction energies for deformed fragments at scission is presented. It has been used to describe the mass-asymmetry-dependent partition of the total energy release on both fragments from spontaneous and induced fission. Characteristic trends of experimental fragment energy and neutron multiplicity data as function of incidence energy in the Th-Cf region of fissioning nuclei are well reproduced. Based on model applications, information on the energy dissipated during the descent from second saddle of fission barrier to scission point have been deduced. (author). 39 refs, 13 figs

  5. Gamma Radiation from Fission Fragments

    Energy Technology Data Exchange (ETDEWEB)

    Higbie, Jack

    1969-10-15

    The gamma radiation from the fragments of the thermal neutron fission of {sup 235}U has been investigated, and the preliminary data are presented here with suggestions for further lines of research and some possible interpretations of the data. The data have direct bearing on the fission process and the mode of fragment de-excitation. The parameters measured are the radiation decay curve for the time interval (1 - 7) x 10{sup -10} sec after fission, the photon yield, the total gamma ray energy yield, and the average photon energy. The last three quantities are measured as a function of the fragment mass.

  6. Fission-product source terms

    International Nuclear Information System (INIS)

    Lorenz, R.A.

    1981-01-01

    This presentation consists of a review of fission-product source terms for light water reactor (LWR) fuel. A source term is the quantity of fission products released under specified conditions that can be used to calculate the consequences of the release. The source term usually defines release from breached fuel-rod cladding but could also describe release from the primary coolant system, the reactor containment shell, or the site boundary. The source term would be different for each locality, and the chemical and physical forms of the fission products could also differ

  7. The spectroscopy of fission fragments

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, W.R. [Department of Physics and Astronomy, University of Manchester, Manchester, M13 9PL (United Kingdom); Collaboration: La Direction des Sciences de la Matiere du CEA (FR); Le Fonds National de la Recherche Scientifique de Belgique (BE)

    1998-12-31

    High-resolution measurements on {gamma} rays from fission fragments have provided a rich source of information, unobtainable at the moment in any other way, on the spectroscopy of neutron-rich nuclei. In recent years important data have been obtained on the yrast- and near yrast-structure of neutron-rich fission fragments. We discuss the scope of measurements which can be made on prompt gamma rays from secondary fission fragments, the techniques used in the experiments and some results recently obtained. (author) 24 refs., 8 figs., 1 tab.

  8. The spectroscopy of fission fragments

    International Nuclear Information System (INIS)

    Phillips, W.R.

    1998-01-01

    High-resolution measurements on γ rays from fission fragments have provided a rich source of information, unobtainable at the moment in any other way, on the spectroscopy of neutron-rich nuclei. In recent years important data have been obtained on the yrast- and near yrast-structure of neutron-rich fission fragments. We discuss the scope of measurements which can be made on prompt gamma rays from secondary fission fragments, the techniques used in the experiments and some results recently obtained. (author)

  9. Using data-driven approach for wind power prediction: A comparative study

    International Nuclear Information System (INIS)

    Taslimi Renani, Ehsan; Elias, Mohamad Fathi Mohamad; Rahim, Nasrudin Abd.

    2016-01-01

    Highlights: • Double exponential smoothing is the most accurate model in wind speed prediction. • A two-stage feature selection method is proposed to select most important inputs. • Direct prediction illustrates better accuracy than indirect prediction. • Adaptive neuro fuzzy inference system outperforms data mining algorithms. • Random forest performs the worst compared to other data mining algorithm. - Abstract: Although wind energy is intermittent and stochastic in nature, it is increasingly important in the power generation due to its sustainability and pollution-free. Increased utilization of wind energy sources calls for more robust and efficient prediction models to mitigate uncertainties associated with wind power. This research compares two different approaches in wind power forecasting which are indirect and direct prediction methods. In indirect method, several times series are applied to forecast the wind speed, whereas the logistic function with five parameters is then used to forecast the wind power. In this study, backtracking search algorithm with novel crossover and mutation operators is employed to find the best parameters of five-parameter logistic function. A new feature selection technique, combining the mutual information and neural network is proposed in this paper to extract the most informative features with a maximum relevancy and minimum redundancy. From the comparative study, the results demonstrate that, in the direct prediction approach where the historical weather data are used to predict the wind power generation directly, adaptive neuro fuzzy inference system outperforms five data mining algorithms namely, random forest, M5Rules, k-nearest neighbor, support vector machine and multilayer perceptron. Moreover, it is also found that the mean absolute percentage error of the direct prediction method using adaptive neuro fuzzy inference system is 1.47% which is approximately less than half of the error obtained with the

  10. Comparing carbon capture and storage (CCS) with concentrating solar power (CSP): Potentials, costs, risks, and barriers

    International Nuclear Information System (INIS)

    Lilliestam, Johan; Bielicki, Jeffrey M.; Patt, Anthony G.

    2012-01-01

    Coal power coupled with Carbon [Dioxide] Capture and Storage (CCS), and Concentrating Solar Power (CSP) technologies are often included in the portfolio of climate change mitigation options intended to decarbonize electricity systems. Both of these technologies can provide baseload electricity, are in early stages of maturity, and have benefits, costs, and obstacles. We compare and contrast CCS applied to coal-fired power plants with CSP. At present, both technologies are more expensive than existing electricity-generating options, but costs should decrease with large-scale deployment, especially in the case of CSP. For CCS, technological challenges still remain, storage risks must be clarified, and regulatory and legal uncertainties remain. For CSP, current challenges include electricity transmission and business models for a rapid and extensive expansion of high-voltage transmission lines. The need for international cooperation may impede CSP expansion in Europe. Highlights: ► Both technologies could provide low-carbon base load power. ► Both technologies require new networks, for either CO 2 or power transmission. ► CSP is closer to being a viable technology ready for pervasive diffusion. ► The costs associated with market saturation would be lower for CSP. ► The regulatory changes required for CSP diffusion are somewhat greater than for CCS.

  11. Systems study of tokamak fusion--fission reactors

    International Nuclear Information System (INIS)

    Tenney, F.H.; Bathke, C.G.; Price, W.G. Jr.; Bohlke, W.H.; Mills, R.G.; Johnson, E.F.; Todd, A.M.M.; Buchanan, C.H.; Gralnick, S.L.

    1978-11-01

    This publication reports the results of a two to three year effort at a systematic analysis of a wide variety of tokamak-driven fissioning blanket reactors, i.e., fusion--fission hybrids. It addresses the quantitative problems of determining the economically most desirable mix of the two products: electric power and fissionable fuel and shows how the price of electric power can be minimized when subject to a variety of constraints. An attempt has been made to avoid restricting assumptions, and the result is an optimizing algorithm that operates in a six-dimensional parameter space. Comparisons are made on sets of as many as 100,000 distinct machine models, and the principal results of the study have been derived from the examination of several hundred thousand possible reactor configurations

  12. Fission dynamics with systems of intermediate fissility

    Indian Academy of Sciences (India)

    results concerning nuclear dissipation and fission time-scale obtained from several of these studies. In particular ... alent to the assumption that fission is delayed, namely, that the fission probability is not .... parameters to be adjusted on the experimental data. ..... (b) Time distribution of all fission events for the 132Ce nucleus.

  13. Remarks on the fission barriers of super-heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, S. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Goethe-Universitaet Frankfurt, Institut fuer Physik, Frankfurt (Germany); Heinz, S.; Mann, R.; Maurer, J.; Muenzenberg, G.; Barth, W.; Dahl, L.; Kindler, B.; Kojouharov, I.; Lang, R.; Lommel, B.; Runke, J.; Scheidenberger, C.; Tinschert, K. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Antalic, S. [Comenius University, Department of Nuclear Physics and Biophysics, Bratislava (Slovakia); Eberhardt, K.; Thoerle-Pospiech, P.; Trautmann, N. [Johannes Gutenberg-Universitaet Mainz, Mainz (Germany); Grzywacz, R. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of Tennessee, Knoxville, TN (United States); Hamilton, J.H. [Vanderbilt University, Department of Physics and Astronomy, Nashville, TN (United States); Henderson, R.A.; Kenneally, J.M.; Moody, K.J.; Shaughnessy, D.A.; Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Miernik, K. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of Warsaw, Warsaw (Poland); Miller, D. [University of Tennessee, Knoxville, TN (United States); Morita, K. [RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama (Japan); Nishio, K. [Japan Atomic Energy Agency, Tokai, Ibaraki (Japan); Popeko, A.G.; Yeremin, A.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Roberto, J.B.; Rykaczewski, K.P. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Uusitalo, J. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland)

    2016-04-15

    Shell-correction energies of super-heavy nuclei are approximated by using Q{sub α} values of measured decay chains. Five decay chains were analyzed, which start at the isotopes {sup 285}Fl, {sup 294}118, {sup 291}Lv, {sup 292}Lv and {sup 293}Lv. The data are compared with predictions of macroscopic-microscopic models. Fission barriers are estimated that can be used to eliminate uncertainties in partial fission half-lives and in calculations of evaporation-residue cross-sections. In that calculations, fission probability of the compound nucleus is a major factor contributing to the total cross-section. The data also provide constraints on the cross-sections of capture and quasi-fission in the entrance channel of the fusion reaction. Arguments are presented that fusion reactions for synthesis of isotopes of elements 118 and 120 may have higher cross-sections than assumed so far. (orig.)

  14. Ternary fission in an effective liquid drop model

    International Nuclear Information System (INIS)

    Duarte, Sergio B.; Tavares, Odilon A.P.; Dimarco, A.; Goncalves, Marcello; Guzman, Fernando; Trallero-Herrera, Carlos; Rodriguez, Oscar; Garcia, Fermin

    2001-01-01

    Full text follows: The nuclear partition in three fragments has been observed in recent experiments for fission process of 252 Cf and 24 '0 Pu. We apply the Effective Liquid Drop Model (ELDM), successfully used for discussing binary cold fission and cluster emissions for a three center geometric shape parametrization, describing the quasi-molecular deformation which can lead to ternary fragmentation. A preliminary calculation for rates of these processes are performed and the results are compared to the rate of the dominant binary fission process. A large range of parent nuclei (spherical and deformed) is covered in the calculation. The purpose is to point out others possible ternary fission process experimentally measurable. (author)

  15. Determination of relative krypton fission product yields from 14 MeV neutron induced fission of 238U at the National Ignition Facility.

    Science.gov (United States)

    Edwards, E R; Cassata, W S; Velsko, C A; Yeamans, C B; Shaughnessy, D A

    2016-11-01

    Precisely-known fission yield distributions are needed to determine a fissioning isotope and the incident neutron energy in nuclear security applications. 14 MeV neutrons from DT fusion at the National Ignition Facility induce fission in depleted uranium contained in the target assembly hohlraum. The fission yields of Kr isotopes (85m, 87, 88, and 89) are measured relative to the cumulative yield of 88 Kr and compared to previously tabulated values. The results from this experiment and England and Rider are in agreement, except for the 85m Kr/ 88 Kr ratio, which may be the result of incorrect nuclear data.

  16. Comparative research of finite element methods for perforated structures of nuclear power plant primary equipment

    International Nuclear Information System (INIS)

    Xiong Guangming; Deng Xiaoyun; Jin Ting

    2013-01-01

    Many perforated structures are used for nuclear power plant primary equipment, and they are complex, and have various forms. In order to explore the analysis and evaluation method, this paper used finite element method and equivalent analytic method to do the comparative analysis of perforated structures. The paper considered the main influence factors (including perforated forms, arrangements, and etc.), obtaining the systematic analysis methods of perforated structures. (authors)

  17. Fusion-fission energy systems evaluation

    International Nuclear Information System (INIS)

    Teofilo, V.L.; Aase, D.T.; Bickford, W.E.

    1980-01-01

    This report serves as the basis for comparing the fusion-fission (hybrid) energy system concept with other advanced technology fissile fuel breeding concepts evaluated in the Nonproliferation Alternative Systems Assessment Program (NASAP). As such, much of the information and data provided herein is in a form that meets the NASAP data requirements. Since the hybrid concept has not been studied as extensively as many of the other fission concepts being examined in NASAP, the provided data and information are sparse relative to these more developed concepts. Nevertheless, this report is intended to provide a perspective on hybrids and to summarize the findings of the rather limited analyses made to date on this concept

  18. Fusion-fission energy systems evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Teofilo, V.L.; Aase, D.T.; Bickford, W.E.

    1980-01-01

    This report serves as the basis for comparing the fusion-fission (hybrid) energy system concept with other advanced technology fissile fuel breeding concepts evaluated in the Nonproliferation Alternative Systems Assessment Program (NASAP). As such, much of the information and data provided herein is in a form that meets the NASAP data requirements. Since the hybrid concept has not been studied as extensively as many of the other fission concepts being examined in NASAP, the provided data and information are sparse relative to these more developed concepts. Nevertheless, this report is intended to provide a perspective on hybrids and to summarize the findings of the rather limited analyses made to date on this concept.

  19. Fission product release from SLOWPOKE-2 reactors

    Energy Technology Data Exchange (ETDEWEB)

    Harnden-Gillis, A M.C. [Queen` s Univ., Kingston, ON (Canada). Dept. of Physics

    1994-12-31

    Increasing radiation fields at several SLOWPOKE-2 reactors fuelled with highly enriched uranium aluminum alloy fuel have begun to interfere with the daily operation of these reactors. To investigate this phenomenon, samples of reactor container water and gas from the headspace were obtained at four SLOWPOKE-2 reactor facilities and examined by gamma ray spectroscopy methods. These radiation fields are due to the circulation of fission products within the reactor container vessel. The most likely source of the fission product release is an area of uranium-bearing material exposed to the coolant at the end weld line which originated at the time of fuel fabrication. The results of this study are compared with observations from an underwater visual examination of one core and the metallographic examination of archived fuel elements. 19 refs., 4 tabs., 8 figs.

  20. Angular distributions in quasi-fission reactions

    International Nuclear Information System (INIS)

    Luetzenkirchen, K.; Kratz, J.V.; Lucas, R.; Poitou, J.; Gregoire, C.; Wirth, G.; Bruechle, W.; Suemmerer, K.

    1985-10-01

    Angular distributions for fission-like fragments were measured in the systems 50 Ti, 56 Fe + 208 Pb by applying an off-line KX-ray activation technique. The distributions d 2 sigma/dTHETAdZ exhibit forward-backward asymmetries that are strongly Z-dependent. They result from a process (quasi-fission) which yields nearly symmetric masses in times comparable to the rotational period of the composite system. A method for obtaining the variance of the tilting angular momentum, K 0 2 , from these skewed, differential angular distributions is described. The results indicate that the tilting mode is not fully excited in quasi-fission reactions. The results are compared to the sum of the variances of all statistical spin components, measured via γ-multiplicities. Integration of the angular distributions d 2 sigma/dTHETAdZ over all values of Z yields integral angular distributions dsigma/dTHETA and dsigma/dΩ symmetric around 90 0 . The associated unusually large anisotropies do not at all provide an adequate basis for tests or modifications of the transition state theory. A deconvolution of d 2 sigma/dTHETAdZ is performed with gaussian distributions depending on rotational angles ΔTHETA extending over a range of up to 540 0 . From the mean values a time scale for the evolution of K 0 is calculated. (orig.)

  1. Fusion--fission hybrid concepts for laser-induced fusion

    International Nuclear Information System (INIS)

    Maniscalco, J.

    1976-01-01

    Fusion-fission hybrid concepts are viewed as subcritical fission reactors driven and controlled by high-energy neutrons from a laser-induced fusion reactor. Blanket designs encompassing a substantial portion of the spectrum of different fission reactor technologies are analyzed and compared by calculating their fissile-breeding and fusion-energy-multiplying characteristics. With a large number of different fission technologies to choose from, it is essential to identify more promising hybrid concepts that can then be subjected to in-depth studies that treat the engineering safety, and economic requirements as well as the neutronic aspects. In the course of neutronically analyzing and comparing several fission blanket concepts, this work has demonstrated that fusion-fission hybrids can be designed to meet a broad spectrum of fissile-breeding and fusion-energy-multiplying requirements. The neutronic results should prove to be extremely useful in formulating the technical scope of future studies concerned with evaluating the technical and economic feasibility of hybrid concepts for laser-induced fusion

  2. Fission gas in thoria

    Energy Technology Data Exchange (ETDEWEB)

    Kuganathan, Navaratnarajah, E-mail: n.kuganathan@imperial.ac.uk [Department of Materials, Faculty of Engineering, Imperial College, London, SW7 2AZ (United Kingdom); Ghosh, Partha S. [Material Science Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Galvin, Conor O.T. [Department of Materials, Faculty of Engineering, Imperial College, London, SW7 2AZ (United Kingdom); Arya, Ashok K. [Material Science Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Dutta, Bijon K. [Homi Bhabha National Institute, Trombay, Mumbai 400 094 (India); Dey, Gautam K. [Material Science Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Grimes, Robin W. [Department of Materials, Faculty of Engineering, Imperial College, London, SW7 2AZ (United Kingdom)

    2017-03-15

    The fission gases Xe and Kr, formed during normal reactor operation, are known to degrade fuel performance, particularly at high burn-up. Using first-principles density functional theory together with a dispersion correction (DFT + D), in ThO{sub 2} we calculate the energetics of neutral and charged point defects, the di-vacancy (DV), different neutral tri-vacancies (NTV), the charged tetravacancy (CTV) defect cluster geometries and their interaction with Xe and Kr. The most favourable incorporation point defect site for Xe or Kr in defective ThO{sub 2} is the fully charged thorium vacancy. The lowest energy NTV in larger supercells of ThO{sub 2} is NTV3, however, a single Xe atom is most stable when accommodated within a NTV1. The di-vacancy (DV) is a significantly less favoured incorporation site than the NTV1 but the CTV offers about the same incorporation energy. Incorporation of a second gas atom in a NTV is a high energy process and more unfavourable than accommodation within an existing Th vacancy. The bi-NTV (BNTV) cluster geometry studied will accommodate one or two gas atoms with low incorporation energies but the addition of a third gas atom incurs a high energy penalty. The tri-NTV cluster (TNTV) forms a larger space which accommodates three gas atoms but again there is a penalty to accommodate a fourth gas atom. By considering the energy to form the defect sites, solution energies were generated showing that in ThO{sub 2−x} the most favourable solution equilibrium site is the NTV1 while in ThO{sub 2} it is the DV. - Highlights: • We have considered Xe and Kr in point defects and defect clusters (neutral and charged) using Density Functional Theory (DFT) with a dispersion correction. • The most favourable charge state for a point defect (vacancy or interstitial) is that with full ionic charge and we have found that in all cases gas atoms occupy the fully charged vacancy sites. • The number of fission gas atoms accommodated in ThO{sub 2} is

  3. Chemical effects of fission recoils

    International Nuclear Information System (INIS)

    Meisels, G.G.; Freeman, J.P.; Gregory, J.P.; Richardson, W.C.; Sroka, G.J.

    1978-01-01

    The production of nitrogen from nitrous oxide at high density was employed to investigate the energy deposition efficiency of fission recoils produced from fission of U 235 in uranium-palladium foils clad with platinum. Nitrogen production varied linearly with fission recoil dose from 1.1 x 10 20 to 9.0 x 10 20 eV, and was independent of density between 12.5 and 127.5 g l -1 N 2 O. 16.2 +- 0.8% of the fission recoil energy was deposited external to the foil. Electron microprobe analysis showed some unevenness of new foil and polymer buildup on the surface after irradiation of ethylene-oxygen mixtures. Subsequent irradiation in the presence of nitrous oxide restored some of the original efficiency. This is ascribed to chemical oxidation of the polymer induced by reactive intermediates produced from nitrous oxide. (author)

  4. Extraction chromatography of fission products

    International Nuclear Information System (INIS)

    Bonnevie-Svendsen, M.; Goon, K.

    1978-01-01

    Various cases of using extraction chromatography during analysis of fission products are reviewed. The use of the extraction chromatography method is considered while analysing reprocessed products of nuclear fuel for quantitative radiochemical analysis and control of fission product and actinoide separation during extraction and their chemical state in production solutions. The method is used to obtain pure fractions of typical burnup monitors (neodymium, molybdenum, cerium, cesium, europium, lanthanides) during determination of nuclear fuel burnup degree. While studying the nature of nuclear reactions the method is used to separate quickly short-life isotopes, to purify β-radiator fractions before measuring their half-life periods, to enrich isotopes forming with low output during fission. Examples of using extraction chromatography are given to separate long half-life or stable fission products from spent solutions, to control environment object contamination

  5. Chemical Production using Fission Fragments

    International Nuclear Information System (INIS)

    Dawson, J. K.; Moseley, F.

    1960-01-01

    Some reactor design considerations of the use of fission recoil fragment energy for the production of chemicals of industrial importance have been discussed previously in a paper given at the Second United Nations International Conference on the Peaceful Uses of Atomic Energy [A/Conf. 15/P.76]. The present paper summarizes more recent progress made on this topic at AERE, Harwell. The range-energy relationship for fission fragments is discussed in the context of the choice of fuel system for a chemical production reactor, and the experimental observation of a variation of chemical effect along the length of a fission fragment track is described for the irradiation of nitrogen-oxygen mixtures. Recent results are given on the effect of fission fragments on carbon monoxide-hydrogen gas mixtures and on water vapour. No system investigated to date shows any outstanding promise for large-scale chemical production. (author) [fr

  6. Perspective on the fusion-fission energy concept

    International Nuclear Information System (INIS)

    Liikala, R.C.; Perry, R.T.; Teofilo, V.L.

    1978-01-01

    A concept which has potential for near-term application in the electric power sector of our energy economy is combining fusion and fission technology. The fusion-fission system, called a hybrid, is distinguished from its pure fusion counterpart by incorporation of fertile materials (uranium or thorium) in the blanket region of a fusion machine. The neutrons produced by the fusion process can be used to generate energy through fission events in the blanket or produce fuel for fission reactors through capture events in the fertile material. The performance requirements of the fusion component of hybrids is perceived as being less stringent than those for pure fusion electric power plants. The performance requirements for the fission component of hybrids is perceived as having been demonstrated or could be demonstrated with a modest investment of research and development funds. This paper presents our insights and observations of this concept in the context of why and where it might fit into the picture of meeting our future energy needs. A bibliography of hybrid research is given

  7. Power Doppler flow mapping and four-dimensional ultrasound for evaluating tubal patency compared with laparoscopy.

    Science.gov (United States)

    Soliman, Amr A; Shaalan, Waleed; Abdel-Dayem, Tamer; Awad, Elsayed Elbadawy; Elkassar, Yasser; Lüdders, Dörte; Malik, Eduard; Sallam, Hassan N

    2015-12-01

    To study the accuracy of four-dimensional (4D) ultrasound and power Doppler flow mapping in detecting tubal patency in women with sub-/infertility, and compare it with laparoscopy and chromopertubation. A prospective study. The study was performed in the outpatient clinic and infertility unit of a university hospital. The sonographic team and laparoscopic team were blinded to the results of each other. Women aged younger than 43 years seeking medical advice due to primary or secondary infertility and who planned to have a diagnostic laparoscopy performed, were recruited to the study after signing an informed consent. All of the recruited patients had power Doppler flow mapping and 4D hysterosalpingo-sonography by injecting sterile saline into the fallopian tubes 1 day before surgery. Registering Doppler signals, while using power Doppler, both at the tubal ostia and fimbrial end and the ability to demonstrate the course of the tube especially the isthmus and fimbrial end, while using 4D mode, was considered a patent tube. Out of 50 recruited patients, 33 women had bilateral patent tubes and five had unilateral patent tubes as shown by chromopertubation during diagnostic laparoscopy. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for two-dimensional power Doppler hysterosalpingography were 94.4%, 100%, 100%, 89.2%, and 96.2%, respectively and for 4D ultrasound were 70.4%, 100%, 100%, 70.4%, and 82.6%, respectively. Four-dimensional saline hysterosalpingography has acceptable accuracy in detecting tubal patency, but is surpassed by power Doppler saline hysterosalpingography. Power Doppler saline hysterosalpingography could be incorporated into the routine sub-/infertility workup. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  8. Fission gas release and grain growth in THO2-UO2 fuel irradiated at high temperature

    International Nuclear Information System (INIS)

    Goldberg, I.; Waldman, L.A.; Giovengo, J.F.; Campbell, W.R.

    1979-01-01

    Data are presented on fission gas release and grain growth in ThO 2 -UO 2 fuels irradiated as part of the LWBR fuel element development program. These data for rods that experienced peak linear power outputs ranging from 15 to 22 KW/ft supplement fission gas release data previously reported for 51 rods containing ThO 2 and ThO 2 -UO 2 fuel irradiated at peak linear powers predominantly below 14 KW/ft. Fission gas release was relatively high (up to 15.0 percent) for the rods operated at high power in contrast to the relatively low fission gas release (0.1 to 5.2 percent) measured for the rods operated at lower power. Metallographic examination revealed extensive equiaxed grain growth in the fuel at the high power axial locations of the three rods

  9. Photovoltaic power stations in Germany and the United States: A comparative study by data envelopment analysis

    International Nuclear Information System (INIS)

    Sueyoshi, Toshiyuki; Goto, Mika

    2014-01-01

    This study compares Photovoltaic (PV) power stations between Germany and the United States to examine which country more efficiently provides renewable energy in their usages. For the comparative analysis, this study utilizes Data Envelopment Analysis (DEA) as a methodology to evaluate the performance of PV power stations from the perspective of both solar and land usages. A total of one hundred sixty PV power stations (eighty in Germany and eighty in the United States) are used for this comparison. The demand for sustainable energy and energy security has been rapidly increasing over the past decade because of concerns about environment and limited resources. PV solutions are one of many renewable technologies that are being developed to satisfy a recent demand of electricity. Germany is the world's top installer and consumer of PV power and the United States is one of the top five nations. Germany leads the way in installed PV capacity even though the nation has less solar resources and land area. Due to limited solar resources, low insolation and sunshine, and land area, the United States should have a clear advantage over Germany. However, the empirical result of this study exhibits that PV power stations in Germany operate more efficiently than those of the United States even if the latter has many solar and land advantages. The surprising result indicates that the United States has room for improvement when it comes to utilizing solar and land resources and needs to reform the solar policy. For such a purpose, Feed-In Tariff (FIT) may be an effective energy policy at the state level in the United States because the FIT provides investors such as utility companies and other types of energy firms with financial incentives to develop large PV power stations and generation facilities for other renewable energy. It may be true that the FIT is a powerful policy tool to promote PV and other renewable installation and support a reduction of an amount of greenhouse

  10. Comparative analysis of concentrating solar power and photovoltaic technologies: Technical and environmental evaluations

    International Nuclear Information System (INIS)

    Desideri, U.; Zepparelli, F.; Morettini, V.; Garroni, E.

    2013-01-01

    Highlights: ► Life cycle was assessed for both concentrated solar power and photovoltaic systems. ► The PV plant has a higher environmental impact than the CSP plant. ► The Global Warming Potential is lower for the CSP than for the PV plant. ► The energy payback time is lower for the CSP than for the PV plant. -- Abstract: Solar energy is an important alternative energy source to fossil fuels and theoretically the most available energy source on the earth. Solar energy can be converted into electric energy by using two different processes: by means of thermodynamic cycles and the photovoltaic conversion. Solar thermal technologies, sometimes called thermodynamic solar technologies, operating at medium (about 500 °C) and high temperatures (about 1000 °C), have recently attracted a renewed interest and have become one of the most promising alternatives in the field of solar energy utilization. Photovoltaic conversion is very interesting, although still quite expensive, because of the absence of moving components and the reduced operating and management costs. The main objectives of the present work are: •to carry out comparative technical evaluations on the amount of electricity produced by two hypothetical plants, located on the same site, for which a preliminary design was made: a solar thermal power plant with parabolic trough collectors and a photovoltaic plant with a single-axis tracking system; •to carry out a comparative analysis of the environmental impact derived from the processes of electricity generation during the whole life cycle of the two hypothetical power plants. First a technical comparison between the two plants was made assuming that they have the same nominal electric power and then the same total covered surface. The methodology chosen to evaluate the environmental impact associated with the power plants is the Life Cycle Assessment (LCA). It allows to analyze all the phases of the life cycle of the plants, from the extraction of

  11. Spontaneous fission of 259Md

    International Nuclear Information System (INIS)

    Hulet, E.K.; Wild, J.F.; Lougheed, R.W.; Baisden, P.A.; Landrum, J.H.; Dougan, R.J.; Mustafa, M.; Ghiorso, A.; Nitschke, J.M.

    1979-01-01

    The mass and kinetic energy distributions of fission fragments from the spontaneous fission of th newly discovered nuclide 259 Md were obtained. 259 Md was identified as the E. C. daughter of 259 No, and was found to decay entirely (> 95%) by spontaneous fission with a 95-min half-life. From the kinetic energies measured for 397 pairs of coincident fragments, a mass distribution was derived that is symmetric with sigma = 13 amu. 259 Md, together with 258 Fm and 259 Fm, form a select group of three nuclides whose mass division in spontaneous fission is highly symmetric. Unlike the total-kinetic-energy (TKE) distributions of 258 Fm and 259 Fm, which peak at approx. = to 240 MeV, this distribution for 259 Md is broad and is 50 MeV lower in energy. Analysis of the mass and energy distributions shows that events near mass symmetry also exhibit a broad TKE distribution, with one-third of the symmetric events having TKEs less than 200 MeV. The associated of low TKEs with symmetric mass division in the fission of very heavy actinides is anomalous and inconsistent with theories based upon the emergence of fragment shells near the scission point. Either three-body fragmentation or peculiar fragment shapes are assumed as the cause for the large consumption of Coulomb energy observed for a significant fraction of symmetric fissions in 259 Md. 6 figures

  12. A stochastic approach to fission

    International Nuclear Information System (INIS)

    Boilley, D.; Suraud, E.; Abe, Yasuhisa

    1992-01-01

    A microscopically derived Langevin equation is applied to thermally induced nuclear fission. An important memory effect is pointed out. A strong friction coefficient, calculated from microscopic quantities, tends to decrease the stationary limit of the fission rate and to increase the transient time. Fission was described as a diffusion over a barrier of a collective variable, and a Langevin Equation (LE) was used to study the phenomenon. A study of the stationary flow over the saddle point with a Fokker-Planck Equation (FPE), equivalent to the LE was used to give formula for the stationary fission rate (or reaction rate for the chemistry applications). More recently, a complete study of the fission process was performed numerically with both FPE and LE. A long transient time, that could allow more pre-scission neutrons to evaporate, was pointed out. The derivation of this new LE is recalled, followed by the description of the memory dependence and by the effect of a large friction coefficient on the fission rate. (author) 6 refs., 3 figs

  13. Comparative evaluation of two models of UPQC for suitable interface to enhance power quality

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Malabika [Department of Electrical Engineering, Dublin Institute of Technology, Kevin Street, Dublin 8 (Ireland); Das, Shyama P.; Dubey, Gopal K. [Department of Electrical Engineering, Indian Institute of Technology, Kanpur (India)

    2007-05-15

    Majority of the dispersed generations from renewable energy sources are connected to the grid through power electronic interface, which introduce additional harmonics in the distribution systems. Research is being carried out to integrate active filtering with specific interface such that a common power quality (PQ) platform could be achieved. For generalized solution, a unified power quality conditioner (UPQC) could be the most comprehensive PQ protecting device for sensitive non-linear loads, which require quality input supply. Also, load current harmonic isolation needs to be ensured for maintaining the quality of the supply current. The present paper describes two control scheme models for UPQC, for enhancing PQ of sensitive non-linear loads. Based on two different kinds of voltage compensation strategy, two control schemes have been designed, which are termed as UPQC-Q and UPQC-P. A comparative loading analysis has developed useful insight in finding the typical application of the two different control schemes. The effectiveness of the two control schemes is verified through extensive simulation using the software SABER. As the power circuit configuration of UPQC remains same for both the model, with modification of control scheme only, the utility of UPQC can be optimized depending upon the application requirement. (author)

  14. Wind turbine power coefficient estimation by soft computing methodologies: Comparative study

    International Nuclear Information System (INIS)

    Shamshirband, Shahaboddin; Petković, Dalibor; Saboohi, Hadi; Anuar, Nor Badrul; Inayat, Irum; Akib, Shatirah; Ćojbašić, Žarko; Nikolić, Vlastimir; Mat Kiah, Miss Laiha; Gani, Abdullah

    2014-01-01

    Highlights: • Variable speed operation of wind turbine to increase power generation. • Changeability and fluctuation of wind has to be accounted. • To build an effective prediction model of wind turbine power coefficient. • The impact of the variation in the blade pitch angle and tip speed ratio. • Support vector regression methodology application as predictive methodology. - Abstract: Wind energy has become a large contender of traditional fossil fuel energy, particularly with the successful operation of multi-megawatt sized wind turbines. However, reasonable wind speed is not adequately sustainable everywhere to build an economical wind farm. In wind energy conversion systems, one of the operational problems is the changeability and fluctuation of wind. In most cases, wind speed can vacillate rapidly. Hence, quality of produced energy becomes an important problem in wind energy conversion plants. Several control techniques have been applied to improve the quality of power generated from wind turbines. In this study, the polynomial and radial basis function (RBF) are applied as the kernel function of support vector regression (SVR) to estimate optimal power coefficient value of the wind turbines. Instead of minimizing the observed training error, SVR p oly and SVR r bf attempt to minimize the generalization error bound so as to achieve generalized performance. The experimental results show that an improvement in predictive accuracy and capability of generalization can be achieved by the SVR approach in compare to other soft computing methodologies

  15. Comparative analysis of supercritical CO2 power conversion system control schemes

    International Nuclear Information System (INIS)

    Vilim, R.B.; Moisseytsev, A.

    2008-01-01

    A comparative analysis of control system performance was carried out for the S-CO 2 re-compressing cycle. In this study two control strategies were developed for managing process variables for a change in load at the electrical generator. Both relied on inventory control to reduce power but differed in other significant respects. In inventory control turbomachine mass flow rates are reduced through density change with the goal of preserving velocity triangle similarity and, hence, cycle efficiency. An inventory and low temperature control scheme was operated to maintain a trajectory that avoids close approach to the critical point by controlling the main compressor inlet temperature. Shaft power tracks a setpoint by controlling density. This control scheme may be preferred in plant configurations that use a flow-split. There the rapid density change with pressure near the critical point can lead to flow rate instability. An inventory and turbine bypass control scheme was operated to more closely approach the critical point. Inventory in addition to turbine bypass was used to control shaft power. The first control scheme yielded greater efficiency at reduced power as a result of two factors. First, bypassing coolant around the turbine increases the mass flow rate through the compressors while shaft speed is maintained constant. As a result the compressor velocity triangles are altered from their peak efficiency values. Second, the bypass flow rate results in non-isothermal mixing downstream where the turbine and bypass flow combine which also penalizes efficiency. (authors)

  16. Radiochemistry and the Study of Fission

    Energy Technology Data Exchange (ETDEWEB)

    Rundberg, Robert S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-11-14

    These are slides from a lecture given at UC Berkeley. Radiochemistry has been used to study fission since its discovery. Radiochemical methods are used to determine cumulative mass yields. These measurements have led to the two-mode fission hypothesis to model the neutron energy dependence of fission product yields. Fission product yields can be used for the nuclear forensics of nuclear explosions. The mass yield curve depends on both the fuel and the neutron spectrum of a device. Recent studies have shown that the nuclear structure of the compound nucleus can affect the mass yield distribution. The following topics are covered: In the beginning: the discovery of fission; forensics using fission products: what can be learned from fission products, definitions of R-values and Q-values, fission bases, K-factors and fission chambers, limitations; the neutron energy dependence of the mass yield distribution (the two mode fission hypothesis); the influence of nuclear structure on the mass yield distribution. In summary: Radiochemistry has been used to study fission since its discovery. Radiochemical measurement of fission product yields have provided the highest precision data for developing fission models and for nuclear forensics. The two-mode fission hypothesis provides a description of the neutron energy dependence of the mass yield curve. However, data is still rather sparse and more work is needed near second and third chance fission. Radiochemical measurements have provided evidence for the importance of nuclear states in the compound nucleus in predicting the mass yield curve in the resonance region.

  17. Radiochemistry and the Study of Fission

    International Nuclear Information System (INIS)

    Rundberg, Robert S.

    2016-01-01

    These are slides from a lecture given at UC Berkeley. Radiochemistry has been used to study fission since its discovery. Radiochemical methods are used to determine cumulative mass yields. These measurements have led to the two-mode fission hypothesis to model the neutron energy dependence of fission product yields. Fission product yields can be used for the nuclear forensics of nuclear explosions. The mass yield curve depends on both the fuel and the neutron spectrum of a device. Recent studies have shown that the nuclear structure of the compound nucleus can affect the mass yield distribution. The following topics are covered: In the beginning: the discovery of fission; forensics using fission products: what can be learned from fission products, definitions of R-values and Q-values, fission bases, K-factors and fission chambers, limitations; the neutron energy dependence of the mass yield distribution (the two mode fission hypothesis); the influence of nuclear structure on the mass yield distribution. In summary: Radiochemistry has been used to study fission since its discovery. Radiochemical measurement of fission product yields have provided the highest precision data for developing fission models and for nuclear forensics. The two-mode fission hypothesis provides a description of the neutron energy dependence of the mass yield curve. However, data is still rather sparse and more work is needed near second and third chance fission. Radiochemical measurements have provided evidence for the importance of nuclear states in the compound nucleus in predicting the mass yield curve in the resonance region.

  18. Determination of the neutron-induced fission cross section of {sup 242}Pu; Bestimmung des neutroneninduzierten Spaltquerschnitts von {sup 242}Pu

    Energy Technology Data Exchange (ETDEWEB)

    Koegler, Toni Joerg

    2016-04-26

    Neutron induced fission cross sections of actinides like the Pu-isotopes are of relevance for the development of nuclear transmutation technologies. For {sup 242}Pu, current uncertainties are of around 21%. Sensitivity studies show that the total uncertainty has to be reduced to below 5% to allow for reliable neutron physics simulations. This challenging task was performed at the neutron time-of-flight facility of the new German National Center for High Power Radiation Sources at HZDR, Dresden. Within the TRAKULA project, thin, large and homogeneous deposits of {sup 235}U and {sup 242}Pu have been produced successfully. Using two consecutively placed fission chambers allowed the determination of the neutron induced fission cross section of {sup 242}Pu relative to {sup 235}U. The areal density of the Plutonium targets was calculated using the measured spontaneous fission rate. Experimental results of the fast neutron induced fission of {sup 242}Pu acquired at nELBE will be presented and compared to recent experiments and evaluated data. Corrections addressing the neutron scattering are discussed by using results of different neutron transport simulations (Geant 4, MCNP 6 and FLUKA).

  19. Comparative Health Risk Assessment of CdTe Solar PV System and Nuclear Power Plant

    International Nuclear Information System (INIS)

    Lee, Sang Hun; Kang, Hyun Gook

    2014-01-01

    In terms of national energy policy decision-making process, several key factors, including low production cost, negligible risk or impact to environment and population around the facility, must be considered. The purpose of this paper is to assess the public health risk in case of postulated nuclear power plant and CdTe solar PV system accident and compare the estimated public health risk. Both systems release toxic materials to the environment which adversely affect nearby population by exposure from the inhalation and ingestion of the toxic material transported via air. By simulating the airborne transport of released toxic material using Gaussian plume model and modeling exposure pathways to nearby population, average individual health risk is assessed and public health risk per power capacity of each system is compared. The result shows that the average public health risk per power capacity of NPP is less than the case of solar PV system. This implies that NPP has lower risk in terms of public health risk in case of severe accident while it can be used as more reliable energy source than renewable energy source so that NPP would take priority over other renewable energy sources in terms of national energy policy

  20. A Comparative Study of CFD Models of a Real Wind Turbine in Solar Chimney Power Plants

    Directory of Open Access Journals (Sweden)

    Ehsan Gholamalizadeh

    2017-10-01

    Full Text Available A solar chimney power plant consists of four main parts, a solar collector, a chimney, an energy storage layer, and a wind turbine. So far, several investigations on the performance of the solar chimney power plant have been conducted. Among them, different approaches have been applied to model the turbine inside the system. In particular, a real wind turbine coupled to the system was simulated using computational fluid dynamics (CFD in three investigations. Gholamalizadeh et al. simulated a wind turbine with the same blade profile as the Manzanares SCPP’s turbine (FX W-151-A blade profile, while a CLARK Y blade profile was modelled by Guo et al. and Ming et al. In this study, simulations of the Manzanares prototype were carried out using the CFD model developed by Gholamalizadeh et al. Then, results obtained by modelling different turbine blade profiles at different turbine rotational speeds were compared. The results showed that a turbine with the CLARK Y blade profile significantly overestimates the value of the pressure drop across the Manzanares prototype turbine as compared to the FX W-151-A blade profile. In addition, modelling of both blade profiles led to very similar trends in changes in turbine efficiency and power output with respect to rotational speed.

  1. Comparative LCA of methanol-fuelled SOFCs as auxiliary power systems on-board ships

    International Nuclear Information System (INIS)

    Strazza, C.; Del Borghi, A.; Costamagna, P.; Traverso, A.; Santin, M.

    2010-01-01

    Fuel cells own the potential for significant environmental improvements both in terms of air quality and climate protection. Through the use of renewable primary energies, local pollutant and greenhouse gas emissions can be significantly minimized over the full life cycle of the electricity generation process, so that marine industry accounts renewable energy as its future energy source. The aim of this paper is to evaluate the use of methanol in Solid Oxide Fuel Cells (SOFC), as auxiliary power systems for commercial vessels, through Life Cycle Assessment (LCA). The LCA methodology allows the assessment of the potential environmental impact along the whole life cycle of the process. The unit considered is a 20 kWel fuel cell system. In a first part of the study different fuel options have been compared (methanol, bio-methanol, natural gas, hydrogen from cracking, electrolysis and reforming), then the operation of the cell fed with methanol has been compared with the traditional auxiliary power system, i.e. a diesel engine. The environmental benefits of the use of fuel cells have been assessed considering different impact categories. The results of the analysis show that fuel production phase has a strong influence on the life cycle impacts and highlight that feeding with bio-methanol represents a highly attractive solution from a life cycle point of view. The comparison with the conventional auxiliary power system shows extremely lower impacts for SOFCs.

  2. Calculation of the Fission Product Release for the HTR-10 based on its Operation History

    International Nuclear Information System (INIS)

    Xhonneux, A.; Druska, C.; Struth, S.; Allelein, H.-J.

    2014-01-01

    Since the first criticality of the HTR-10 test reactor in 2000, a rather complex operation history was performed. As the HTR-10 is the only pebble bed reactor in operation today delivering experimental data for HTR simulation codes, an attempt was made to simulate the whole reactor operation up to the presence. Special emphasis was put on the fission product release behaviour as it is an important safety aspect of such a reactor. The operation history has to be simulated with respect to the neutronics, fluid mechanics and depletion to get a detailed knowledge about the time-dependent nuclide inventory. In this paper we report about such a simulation with VSOP 99/11 and our new fission product release code STACY. While STACY (Source Term Analysis Code System) so far was able to calculate the fission product release rates in case of an equilibrium core and during transients, it now can also be applied to running-in-phases. This coupling demonstrates a first step towards an HCP Prototype. Based on the published power histogram of the HTR-10 and additional information about the fuel loading and shuffling, a coupled neutronics, fluid dynamics and depletion calculation was performed. Special emphasis was put on the complex fuel-shuffling scheme within both VSOP and STACY. The simulations have shown that the HTR-10 up to now generated about 2580 MWd while reshuffling the core about 2.3 times. Within this paper, STACY results for the equilibrium core will be compared with FRESCO-II results being published by INET. Compared to these release rates, which are based on a few user defined life histories, in this new approach the fission product release rates of Ag-110m, Cs-137, Sr-90 and I-131 have been simulated for about 4000 tracer pebbles with STACY. For the calculation of the HTR-10 operation history time-dependent release rates are being presented as well. (author)

  3. Fission of heavy nuclei: microscopic study of fission barriers and fragments angular momentum

    International Nuclear Information System (INIS)

    Bonneau, L.

    2003-11-01

    A lot of experimental data on nuclear fission has been being collected for the last 65 years, allowing theoreticians to confront their models with reality. The first part of this work is dedicated to the computation of fission barriers. We have extended the HF + BCS (Hartree Fock + Bandeen-Cooper-Schrieffer) method in order to include a new set of polynomials on which wave functions can be broken to, more accurately than on Hermite's polynomials in the 2 fragment configuration. The fission barriers of 26 heavy nuclei from Thorium-230 to Nobelium-256 have been assessed and compared to experimental data, it appears that differences are no greater than 1 MeV. We have discovered a neat correlation between the variation of the experimental fission lifetimes of even Fermium isotopes and the computed heights of second barriers. Moreover our model reproduces the hyper-deformed well of Thorium-230 with a good agreement on the well depth. The second part deals with the scission region. We have performed Hartree-Fock calculations in order to explore different ways of fragmentation. We have shown that the harmonic oscillator gives a valid description of such ways. In order to compute the mean value of J 2 in the fragments we have been driven to propose an adequate definition of that quantity consistent with the non-locality property of the J 2 operator. (A.C.)

  4. Properties of Fission-Product decay heat from Minor-Actinide fissioning systems

    International Nuclear Information System (INIS)

    Oyamatsu, Kazuhiro; Mori, Hideki

    2000-01-01

    The aggregate Fission-Product (FP) decay heat after a pulse fission is examined for Minor Actinide (MA) fissiles 237 Np, 241 Am, 243 Am, 242 Cm and 244 Cm. We find that the MA decay heat is comparable but smaller than that of 235 U except for cooling times at about 10 8 s (approx. = 3 y). At these cooling times, either the β or γ component of the FP decay heat for these MA's is substantially larger than the one for 235 U. This difference is found to originate from the cumulative fission yield of 106 Ru (T 1/2 = 3.2x10 7 s). This nuclide is the parent of 106 Rh (T 1/2 = 29.8 s) which is the dominant source of the decay heat at 10 8 s (approx. = 3 y). The fission yield is nearly an increasing function of the fissile mass number so that the FP decay heat is the largest for 244 Cm among the MA's at the cooling time. (author)

  5. Comparative assessment of nuclear power and other options: the DECADES project

    International Nuclear Information System (INIS)

    Vladu, I. F.

    1996-01-01

    This paper presents the results obtained in constructing and implementing a general framework for performing comprehensive assessment within the inter-agency joint project on Databases and Methodologies for Comparative Assessment of Different Energy Sources for electricity generation. The project was established in 1992 by nine international organizations. A short description of the DECADES project objectives, structure and main components is given. The technology inventory databases, which are a major part of the project, address all the levels of different energy chains, from fuel extraction through electricity generation to waste disposal. These databases support comparative assessment in the power sector, by providing generic information as well as country or region specific information on existing technologies and on those expected to enter the market in the next two to three decades. The paper further touches on the types of assessment that can be carried out using the methodology and databases developed. It point out in this regard the possibilities and limitations of comparative assessments performed at the level of power plant, full electricity supply chain and country or region electricity generation system. Illustrative results are presented for comparisons performed at all these levels. Case studies and workshops and seminars are one of the main activities carried out until now for validation and dissemination of the DECADES Computer Tools. In those studies where it was considered, nuclear power appeared to be cost effective for reducing emissions of CO 2 , SO 2 , NO x and other greenhouse gases. Finally, the paper briefly introduce the activities envisaged for the phase II of the DECADES project which will focus on disseminating the current computer tools, providing training in the use of the tools, and supporting country studies, and on development of new analytical capabilities. The paper concludes with some findings and remarks pointing out the

  6. A fission gas release model

    Energy Technology Data Exchange (ETDEWEB)

    Denis, A; Piotrkowski, R [Argentine Atomic Energy Commission, Buenos Aires (Argentina)

    1997-08-01

    The hypothesis contained in the model developed in this work are as follows. The UO{sub 2} is considered as a collection of spherical grains. Nuclear reactions produce fission gases, mainly Xe and Kr, within the grains. Due to the very low solubility of these gases in UO{sub 2}, intragranular bubbles are formed, of a few nanometers is size. The bubbles are assumed to be immobile and to act as traps which capture gas atoms. Free atoms diffuse towards the grain boundaries, where they give origin to intergranular, lenticular bubbles, of the order of microns. The gas atoms in bubbles, either inter or intragranular, can re-enter the matrix through the mechanism of resolution induced by fission fragment impact. The amount of gas stored in intergranular bubbles grows up to a saturation value. Once saturation is reached, intergranular bubbles inter-connect and the gas in excess is released through different channels to the external surface of the fuel. The resolution of intergranular bubbles particularly affects the region of the grain adjacent to the grain boundary. During grain growth, the grain boundary traps the gas atoms, either free or in intragranular bubbles, contained in the swept volume. The grain boundary is considered as a perfect sink, i.e. the gas concentration is zero at that surface of the grain. Due to the spherical symmetry of the problem, the concentration gradient is null at the centre of the grain. The diffusion equation was solved using the implicit finite difference method. The initial solution was analytically obtained by the Laplace transform. The calculations were performed at different constant temperatures and were compared with experimental results. They show the asymptotic growth of the grain radius as a function of burnup, the gas distribution within the grain at every instant, the growth of the gas content at the grain boundary up to the saturation value and the fraction of gas released by the fuel element referred to the total gas generated

  7. The comparative costs of nuclear and fossil fuelled power plants in an American electricity utility

    International Nuclear Information System (INIS)

    Corey, G.R.

    1984-01-01

    This chapter compares the current and historic operating performances of twelve large nuclear and coal-fired units now operated by Commonwealth Edison Company, and provides specific comparison of bus-bar costs of electricity generated by those units in recent years. It also provides cost comparisons for future nuclear and coal-fired units and attempts to deal realistically with the effect of future inflation upon these comparisons. The chapter attempts to deal responsibly with the problem of uncertainty - how present-day comparisons may be affected by future developments and how my own published comparisons have varied over the past four or five years. The conclusion is reached that, given the uncertain world in which we live, no electric power supplier can afford to put all its eggs in one basket. Utility managers have a strong incentive to diversify their sources of power generation, and society as a whole would do well to encourage such diversification. (author)

  8. A comparative study of different transformer connections for railway power supply- mitigation of voltage unbalance

    DEFF Research Database (Denmark)

    Firat, Gurkan; Yang, Guangya; Ali Hussain Al-Ali, Haider

    2015-01-01

    The railway represents a large power consumer that can cause uneven loading of the phases in the high voltage grid. These unbalanced loads supplied by the utility may lead to voltage unbalance problems in the system and thereby affects the other consumers connected to the same network. It is fact...... that, voltage unbalance appears mainly as a result of unbalanced currents at the points of common coupling drawn by unevenly distributed loads. Because of a significant amount of negative sequence current injected to the system, the power system components will suffer from consequent negative effects...... such as overheating, additional losses of lines and transformers, interference with communication systems etc. This paper presents a comparative study of some transformer connections which commonly used in railway supplying AC traction loads, for voltage unbalance mitigations. Simulations for comparison...

  9. Comparative analysis of hourly and dynamic power balancing models for validating future energy scenarios

    DEFF Research Database (Denmark)

    Pillai, Jayakrishnan R.; Heussen, Kai; Østergaard, Poul Alberg

    2011-01-01

    Energy system analyses on the basis of fast and simple tools have proven particularly useful for interdisciplinary planning projects with frequent iterations and re-evaluation of alternative scenarios. As such, the tool “EnergyPLAN” is used for hourly balanced and spatially aggregate annual......, the model is verified on the basis of the existing energy mix on Bornholm as an islanded energy system. Future energy scenarios for the year 2030 are analysed to study a feasible technology mix for a higher share of wind power. Finally, the results of the hourly simulations are compared to dynamic frequency...... simulations incorporating the Vehicle-to-grid technology. The results indicate how the EnergyPLAN model may be improved in terms of intra-hour variability, stability and ancillary services to achieve a better reflection of energy and power capacity requirements....

  10. Two views of the comparative escalation of nuclear and coal-fired power plant costs

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    Doan L. Phung critiques Charles Komanoff's 1981 book Power Plant Cost Escalation, which compares new nuclear plant costs unfavorably with those of new coal plants because of the increase in capital costs. Phung blames prophets of doom who ignore the escalating costs throughout the economy and now focus their anti-nuclear attacks in economic terms. Proposals by Alvin Weinberg and others to concentrate on reactor-safety improvements are used to conclude that these efforts will further expand the capital costs of nuclear plants and make them noncompetitive. Phung questions whether Komanoff's modeling considers enough of the political, regulatory, and technological factors to determine future costs. Komanoff replies by explaining his method of analysis and denying a bias against nuclear power. A postscript by Phung reiterates his criticism of simplistic calculations and extrapolations. 17 references

  11. Comparative analysis for power generation and ethanol production from sugarcane residual biomass in Brazil

    International Nuclear Information System (INIS)

    Seabra, Joaquim E.A.; Macedo, Isaias C.

    2011-01-01

    This work compares the technical, economic and environmental (GHG emissions mitigation) performance of power generation and ethanol production from sugarcane residual biomass, considering conversion plants adjacent to a sugarcane mill in Brazil. Systems performances were simulated for a projected enzymatic saccharification co-fermentation plant (Ethanol option) and for a commercial steam-Rankine power plant (Electricity option). Surplus bagasse from the mill would be used as fuel/raw material for conversion, while cane trash collected from the field would be used as supplementary fuel at the mill. For the Electricity option, the sugarcane biorefinery (mill+adjacent plant) would produce 91 L of ethanol per tonne of cane and export 130 kWh/t of cane, while for the Ethanol option the total ethanol production would be 124 L/t of cane with an electricity surplus of 50 kWh/t cane. The return on investment (ROI) related to the biochemical conversion route was 15.9%, compared with 23.2% for the power plant, for the conditions in Brazil. Considering the GHG emissions mitigation, the environmentally preferred option is the biochemical conversion route: the net avoided emissions associated to the adjacent plants are estimated to be 493 and 781 kgCO 2 eq/t of dry bagasse for the Electricity and Ethanol options, respectively. - Research Highlights: → Power generation would present better profitability than ethanol production from sugarcane residues in Brazil, in the reference scenario adopted here. → The Ethanol option would be able to mitigate more GHG emissions in Brazil. → The economics for the ethanol production technology are more likely to improve in the future.

  12. Contributions to the theory of fission neutron emission

    International Nuclear Information System (INIS)

    Seeliger, D.; Maerten, H.; Ruben, A.

    1990-03-01

    This report gives a compilation of recent work performed at Technical University, Dresden by D. Seeliger, H. Maerten and A. Ruben on the topic of fission neutron emission. In the first paper calculated fission neutron spectra are presented using the temperature distribution model FINESSE for fissioning actinide nuclei. In the second paper, starting from a general energy balance, Terrell's approach is generalized to describe average fragment energies as a function of incident energy; trends of fragment energy data in the Th-Pu region are well reproduced. In the third contribution, prompt fission neutron spectra and fragment characteristics for spontaneous fission of even Pu-isotopes are presented and discussed in comparison with experimental data using a phenomenological scission point model including temperature dependent shell effects. In the fourth paper, neutron multiplicities and energy spectra as well as average fragment energies for incident energies from threshold to 20 MeV (including multiple-chance fission) for U-238 are compared with traditional data representations. (author). Refs, figs and tabs

  13. Measurement of MA fission cross sections at YAYOI

    Energy Technology Data Exchange (ETDEWEB)

    Ohkawachi, Yasushi; Ohki, Shigeo; Wakabayashi, Toshio [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

    1998-03-01

    Fission cross section ratios of minor actinide nuclides (Am-241, Am-243) relative to U-235 in the fast neutron energy region have been measured using a back-to-back (BTB) fission chamber at YAYOI fast neutron source reactor. A small BTB fission chamber was developed to measure the fission cross section ratios in the center of the core at YAYOI reactor. Dependence of the fission cross section ratios on neutron spectra was investigated by changing the position of the detector in the reactor core. The measurement results were compared with the fission cross sections in the JENDL-3.2, ENDF/B-VI and JEF-2.2 libraries. It was found that calculated values of Am-241 using the JENDL-3.2, ENDF/B-VI and JEF-2.2 data are lower by about 15% than the measured value in the center of the core (the neutron average energy is 1.44E+6(eV)). And, good agreement can be seen the measured value and calculated value of Am-243 using the JENDL-3.2 data in the center of the core (the neutron average energy is 1.44E+6)(eV), but calculated values of Am-243 using the ENDF/B-VI and JEF-2.2 data are lower by 11% and 13% than the measured value. (author)

  14. Conceptual design of the blanket and power conversion system for a mirror hybrid fusion-fission reactor. Addendum 1. Alternate concepts. 12-month progress report addendum, July 1, 1975--June 30, 1976

    International Nuclear Information System (INIS)

    Schultz, K.R.; Dee, J.B.; Backus, G.A.; Culver, D.W.

    1976-01-01

    During the course of the Mirror Hybrid Fusion-Fission Reactor study several alternate concepts were considered for various reactor components. Several of the alternate concepts do appear to exhibit features with potential advantage for use in the mirror hybrid reactor. These are described and should possibly be investigated further in the future

  15. Comparative efficacy of two battery-powered toothbrushes on dental plaque removal.

    Science.gov (United States)

    Ruhlman, C Douglas; Bartizek, Robert D; Biesbrock, Aaron R

    2002-01-01

    A number of clinical studies have consistently demonstrated that power toothbrushes deliver superior plaque removal compared to manual toothbrushes. Recently, a new power toothbrush (Crest SpinBrush) has been marketed with a design that fundamentally differs from other marketed power toothbrushes. Other power toothbrushes feature a small, round head designed to oscillate for enhanced cleaning between the teeth and below the gumline. The new power toothbrush incorporates a similar round oscillating head in conjunction with fixed bristles, which allows the user to brush with optimal manual brushing technique. The objective of this randomized, examiner-blind, parallel design study was to compare the plaque removal efficacy of a positive control power toothbrush (Colgate Actibrush) to an experimental toothbrush (Crest SpinBrush) following a single use among 59 subjects. Baseline plaque scores were 1.64 and 1.40 for the experimental toothbrush and control toothbrush treatment groups, respectively. With regard to all surfaces examined, the experimental toothbrush delivered an adjusted (via analysis of covariance) mean difference between baseline and post-brushing plaque scores of 0.47, while the control toothbrush delivered an adjusted mean difference of 0.33. On average, the difference between toothbrushes was statistically significant (p = 0.013). Because the covariate slope for the experimental group was statistically significantly greater (p = 0.001) than the slope for the control group, a separate slope model was used. Further analysis demonstrated that the experimental group had statistically significantly greater plaque removal than the control group for baseline plaque scores above 1.43. With respect to buccal surfaces, using a separate slope analysis of covariance, the experimental toothbrush delivered an adjusted mean difference between baseline and post-brushing plaque scores of 0.61, while the control toothbrush delivered an adjusted mean difference of 0

  16. Future trends in the assessment of hazards from fission product releases

    Energy Technology Data Exchange (ETDEWEB)

    Beattie, J. R.

    1983-11-15

    In comparing and selecting sites for reactors from the point of view of safety, one considers the remote possibility of an accidental release of moderately large amounts of fission products and its effects in relation to the present and future distribution of population in the neighbourhood. At present, until experience is gained of the reliability and safety of reactors, there is a tendency to site them remotely from centres of industry and population, although for economic reasons there will be a need to site large power reactors more closely to such centres in the future. With, among other objectives, the aim of adopting, in the proper course or time, less restrictive siting criteria, improvements are continually made in the intrinsic safety of reactor system and more sophisticated forms of reactor containment are devised, in order to reduce the possibility and scale of any fission product release. Changes and improvements in reactor systems could affect the nature and proportion of an accidental release of fission products if this should occur in the future. It is appropriate to consider what such a release and its radiobiological effects might be.

  17. Burn-up calculation of fusion-fission hybrid reactor using thorium cycle

    International Nuclear Information System (INIS)

    Shido, S.; Matsunaka, M.; Kondo, K.; Murata, I.; Yamamoto, Y.

    2006-01-01

    A burn-up calculation system has been developed to estimate performance of blanket in a fusion-fission hybrid reactor which is a fusion reactor with a blanket region containing nuclear fuel. In this system, neutron flux is calculated by MCNP4B and then burn-up calculation is performed by ORIGEN2. The cross-section library for ORIGEN2 is made from the calculated neutron flux and evaluated nuclear data. The 3-dimensional ITER model was used as a base fusion reactor. The nuclear fuel (reprocessed plutonium as the fission materials mixed with thorium as the fertile materials), transmutation materials (minor actinides and long-lived fission products) and tritium breeder were loaded into the blanket. Performances of gas-cooled and water-cooled blankets were compared with each other. As a result, the proposed reactor can meet the requirement for TBP and power density. As far as nuclear waste incineration is concerned, the gas-cooled blanket has advantages. On the other hand, the water cooled-blanket is suited to energy production. (author)

  18. The Fukushima nuclear disaster and its effects on media framing of fission and fusion energy technologies

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Luisa; Horta, Ana; Pereira, Sergio; Delicado, Ana [Institute of Social Sciences of the University of Lisbon, Av. Prof. Anibal de Bettencourt, 9 1600-189 Lisbon (Portugal)

    2015-07-01

    This paper presents results of a comparison of media coverage of fusion and fission energy technologies in three countries (Germany, Spain and Portugal) and in the English language international print media addressing transnational elite, from 2008 to 2012. The analysis showed that the accident in Fukushima in March 2010 did not have significant impact on media framing of nuclear fusion in the major part of print media under investigation. In fact, fusion is clearly dissociated from traditional nuclear (fission) energy and from nuclear accidents. It tends to be portrayed as a safe, clean and unlimited source of energy, although less credited when confronted with research costs, technological feasibility and the possibility to be achieved in a reasonable period of time. On the contrary, fission is portrayed as a hazardous source of energy, expensive when compared to research costs of renewables, hardly a long-term energy option, susceptible to contribute to the proliferation of nuclear weapons or rogue military use. Fukushima accident was consistently discussed in the context of safety problems of nuclear power plants and in many cases appeared not as an isolated event but rather as a reminder of previous nuclear disasters such as Three Miles Island and Chernobyl. (authors)

  19. The Fukushima nuclear disaster and its effects on media framing of fission and fusion energy technologies

    International Nuclear Information System (INIS)

    Schmidt, Luisa; Horta, Ana; Pereira, Sergio; Delicado, Ana

    2015-01-01

    This paper presents results of a comparison of media coverage of fusion and fission energy technologies in three countries (Germany, Spain and Portugal) and in the English language international print media addressing transnational elite, from 2008 to 2012. The analysis showed that the accident in Fukushima in March 2010 did not have significant impact on media framing of nuclear fusion in the major part of print media under investigation. In fact, fusion is clearly dissociated from traditional nuclear (fission) energy and from nuclear accidents. It tends to be portrayed as a safe, clean and unlimited source of energy, although less credited when confronted with research costs, technological feasibility and the possibility to be achieved in a reasonable period of time. On the contrary, fission is portrayed as a hazardous source of energy, expensive when compared to research costs of renewables, hardly a long-term energy option, susceptible to contribute to the proliferation of nuclear weapons or rogue military use. Fukushima accident was consistently discussed in the context of safety problems of nuclear power plants and in many cases appeared not as an isolated event but rather as a reminder of previous nuclear disasters such as Three Miles Island and Chernobyl. (authors)

  20. Fission of Polyanionic Metal Clusters

    Science.gov (United States)

    König, S.; Jankowski, A.; Marx, G.; Schweikhard, L.; Wolfram, M.

    2018-04-01

    Size-selected dianionic lead clusters Pbn2 -, n =34 - 56 , are stored in a Penning trap and studied with respect to their decay products upon photoexcitation. Contrary to the decay of other dianionic metal clusters, these lead clusters show a variety of decay channels. The mass spectra of the fragments are compared to the corresponding spectra of the monoanionic precursors. This comparison leads to the conclusion that, in the cluster size region below about n =48 , the fission reaction Pbn2 -→Pbn-10 -+Pb10- is the major decay process. Its disappearance at larger cluster sizes may be an indication of a nonmetal to metal transition. Recently, the pair of Pb10- and Pbn-10 - were observed as pronounced fragments in electron-attachment studies [S. König et al., Int. J. Mass Spectrom. 421, 129 (2017), 10.1016/j.ijms.2017.06.009]. The present findings suggest that this combination is the fingerprint of the decay of doubly charged lead clusters. With this assumption, the dianion clusters have been traced down to Pb212 -, whereas the smallest size for the direct observation was as high as n =28 .

  1. Fission blanket benchmark experiment on spherical assembly of uranium and PE with PE reflector

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Tonghua; Lu, Xinxin; Wang, Mei; Han, Zijie, E-mail: neutron_integral@aliyun.com; Jiang, Li; Wen, Zhongwei; Liu, Rong

    2016-04-15

    Highlights: • The fission rate distribution on two depleted uranium assemblies was measured with plate fission chambers. • We do calculations using MCNP code and ENDF/B-V.0 library. • The overestimation of calculations to the measured fission rates was found. • The observed discrepancy are discussed. - Abstract: New concept of fusion-fission hybrid for energy generation has been proposed. To validate the nuclear performance of fission blanket of hybrid, as part of series of validation experiment, two types of fission blanket assemblies were setup in this work and measurements were made of the reaction rate distribution for uranium fission in the spherical assembly of depleted uranium and polyethylene by Plate Fission Chamber (PFC). There are two PFCs in experiment, one is depleted uranium chamber and the other is enriched uranium chamber. The Monte-Carlo transport code MCNP5 and continuous energy cross sections library ENDF/BV.0 were used for the analysis of fission rate distribution in the two types of assemblies. The calculated results were compared with the experimental ones. The overestimation of fission rate for depleted uranium and enriched uranium were found in the inner boundary of the two assemblies. However, the C/E ratio tends to decrease for the distance from the core slightly and the results for enriched uranium are better than that for depleted uranium.

  2. Evaluations of fusion-fission (hybrid) concepts: market penetration analysis for fusion-fission hybrids. Part A

    International Nuclear Information System (INIS)

    Engel, R.L.; Deonigi, D.E.

    1976-01-01

    This report summarizes findings of the fusion-fission studies conducted for the Electric Power Research Institute by Battelle, Pacific Northwest Laboratories. This particular study focused on the evaluation of fissile material producing hybrids. Technical results of the evaluation of actinide burning are presented in a companion volume, Part B

  3. Lambda attachment in fission: a probe of the necking dynamics

    International Nuclear Information System (INIS)

    Nifenecker, H.; Malek, F.

    1991-02-01

    A schematic scission model is applied to the lambda attachment function recently obtained by the LEAR PS177 collaboration, in their measurement of the prompt fission of hypernuclei. The relationship between the slope parameter and the fission dynamics was examined in a more quantitative way. It is shown that the attachment function is sensitive to the scission configuration, necking dynamics and nuclear temperature at scission. It provides a new and powerful way to study the nuclear scission process. (R.P.) 19 refs., 9 figs

  4. Problems to be Expected in Disposing of Fission Products from a Possible Nuclear Power Programme; Problemes Eventuels d'Elimination des Produits de Fission dans les Futures Centrales Nucleaires; 0412 0415 0420 041e 042f 0414 ; Problemas que Puede Plantear la Evacuacion de Productos de Fision Resultantes de la Ejecucion de un Programa de Produccion de Energia de Origen Nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Dickson, G. K. [Cenral Technical Services, Engineering and Development Group, United Kingdom Atomic Energy Authority, Risley (United Kingdom)

    1960-07-01

    typical British nuclear power programme covering the next few decades is examined. The types of reactor to be erected and the types of fuel to be initially used in them are well appreciated but of course the author's conclusions will necessarily become less certain with the passage of time. The chemical processes which must be applied to irradiated fuels will depend on the type of fuel, its burn-up etc., and so will change during the period under review. Consideration is therefore given to the quantities of fission products and heavy isotopes which may be produced, the forms in which they may leave the chemical processing streams and the methods available for handling them safely, either by storage or by disposal. (author) [French] L'auteur examine un programme d'energie nucleaire caracteristique pour la Grande-Bretagne et s'etendant sur les prochaines decennies. Il donne une evaluation fort judicieuse des types de reacteurs dont la construction est envisagee et des genres de combustibles qu'il est question d'y utiliser pendant la periode initiale; toutefois, ses conclusions auront avec le temps de moins en moins de valeur. En effet, le traitement chimique auquel on devra soumettre le combustible irradie depend du genre de ce dernier, de son taux de combustion, etc.; il subira inevitablement des modifications au cours de la periode consideree. L'auteur tient donc compte des quantites de produits fissiles et d'isotopes lourds qu'il sera possible de produire, des formes sous lesquelles ils pourront se presenter a la fin du traitement chimique et des methodes existantes permettant d'assurer leur manipulation sans danger en vue de leur stockage ou de leur elimination. (author) [Spanish] Esta memoria estudia un programa britanico caracteristico de produccion de energia nuclear que cubre las proximas decadas. Se sabe con bastante certeza que tipos de reactores se construiran y el tipo de combustible que se empleara en ellos en un principio, pero estos conocimientos son

  5. FREVAP-6, Metal Fission Products Release from HTGR Fuel Elements

    International Nuclear Information System (INIS)

    Pierce, V.H.

    2005-01-01

    1 - Description of problem or function: The FREVAP type of code for estimating the release of longer-lived metallic fission products from HTGR fuel elements has been developed to take into account the combined effects of the retention of metallic fission products by fuel particles and the rather strong absorption of these fission products by the graphite of the fuel elements. Release calculations are made on the basis that the loss of fission product nuclides such as strontium, cesium, and barium is determined by their evaporation from the graphite surfaces and their transpiration induced by the flowing helium coolant. The code is devised so that changes of fission rate (fuel element power), fuel temperature, and graphite temperature may be incorporated into the calculation. Temperature is quite important in determining release because, in general, both release from fuel particles and loss by evaporation (transpiration) vary exponentially with the reciprocal of the absolute temperature. NESC0301/02: This version differs from the previous one in the following points: The source and output files were converted from BCD to ASCII coding. 2 - Method of solution: A problem is defined as having a one-dimensional segment made up of three parts - (1) the fission product source (fuel particles) in series with, (2) a non-source and absorption part (element graphite) and (3) a surface for evaporation to the coolant (graphite-helium interface). More than one segment may be connected (possibly segments stacked axially) by way of the coolant. At any given segment, a continuity equation is solved assuming equilibrium between the source term, absorption term, evaporation at coolant interface and the partial pressure of the fission product isotope in the coolant. 3 - Restrictions on the complexity of the problem - Maxima of: 5 isotopes; 10 time intervals for time-dependent variable; 49 segments (times number of isotopes); 5 different output print time-steps

  6. Putting risk analysis into perspective: a comparative review of major societal risk studies of nuclear power

    International Nuclear Information System (INIS)

    Dooley, J.E.; Hansson, B.; Kaspersson, R.; ORiordan, T.; Paschen, H.

    1983-04-01

    The emphasis in this final report of the project Evaluation of major Swedish energy risk assessments in an international perspective is shifted towards the comparative aspect. The comprehensive nuclear risk study has been used as an instrument to satisfy many needs simultaneously. The research consisted of an examination of existing risk studies of five nations, namely West Germany, UK, US, Canada and Sweden. The effect of nuclear risk studies on society at large and on public attitude towards nuclear power in particular is discussed. Finally, the effect on the nuclear establishment is analysed. (G.B.)

  7. Productivity and compensation by purchase power parity in Ukraine and other countries: comparative analysis

    OpenAIRE

    M. Sokolyk

    2011-01-01

    The trends of the real growth rates of the GDP, of productivity and wages per employee and of aver-age monthly salary in Ukraine for a long period of time (1990-2010) are evaluated in this article. The author makes comparative analysis of labor productivity and wages per one employee on the basis of the data on purchasing power parity in Ukraine and in other countries during the pre-crisis period. He justifies the measures to bring the levels of labor productivity and compensation per employe...

  8. COMPARATIVE ANALYSIS ON PERFORMANCE OF POWER CONVERTERSFOR MPPT USING PAO TECHNIQUE

    OpenAIRE

    Dr. S. Rajeswari*

    2017-01-01

    This research work is mainly spotlight to identify a suitable power converter for tracking the Maximum Power Point, an analysis of MPPT based power converters has been carried out in this work. A PV system is a non-linear power source due to the variations in the climatic conditions, hence tracking the maximum power point is difficult. It mainly explains about the PAO algorithm based MPPT method to track the maximum power. It also discuss about different types of conventional power converters...

  9. The LANL C-NR counting room and fission product yields

    Energy Technology Data Exchange (ETDEWEB)

    Jackman, Kevin Richard [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

    2015-09-21

    This PowerPoint presentation focused on the following areas: LANL C-NR counting room; Fission product yields; Los Alamos Neutron wheel experiments; Recent experiments ad NCERC; and Post-detonation nuclear forensics

  10. Innovative High Temperature Heat Pipes for Spacecraft Nuclear Fission Systems, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA Glenn is examining small fission reactors for future space transportation and surface power applications. The reactors would have an 8 to 15 year design life...

  11. Challenges faced by China compared with the US in developing wind power

    Science.gov (United States)

    Lu, Xi; McElroy, Michael B.; Peng, Wei; Liu, Shiyang; Nielsen, Chris P.; Wang, Haikun

    2016-06-01

    In the 21st Conference of the Parties held in Paris in December 2015, China pledged to peak its carbon emissions and increase non-fossil energy to 20% by 2030 or earlier. Expanding renewable capacity, especially wind power, is a central strategy to achieve these climate goals. Despite greater capacity for wind installation in China compared to the US (145.1 versus 75.0 GW), less wind electricity is generated in China (186.3 versus 190.9 TWh). Here, we quantify the relative importance of the key factors accounting for the unsatisfactory performance of Chinese wind farms. Different from the results in earlier qualitative studies, we find that the difference in wind resources explains only a small fraction of the present China-US difference in wind power output (-17.9% in 2012); the curtailment of wind power, differences in turbine quality, and delayed connection to the grid are identified as the three primary factors (respectively -49.3%, -50.2%, and -50.3% in 2012). Improvements in both technology choices and the policy environment are critical in addressing these challenges.

  12. A comparative study of the maximum power point tracking methods for PV systems

    International Nuclear Information System (INIS)

    Liu, Yali; Li, Ming; Ji, Xu; Luo, Xi; Wang, Meidi; Zhang, Ying

    2014-01-01

    Highlights: • An improved maximum power point tracking method for PV system was proposed. • Theoretical derivation procedure of the proposed method was provided. • Simulation models of MPPT trackers were established based on MATLAB/Simulink. • Experiments were conducted to verify the effectiveness of the proposed MPPT method. - Abstract: Maximum power point tracking (MPPT) algorithms play an important role in the optimization of the power and efficiency of a photovoltaic (PV) generation system. According to the contradiction of the classical Perturb and Observe (P and Oa) method between the corresponding speed and the tracking accuracy on steady-state, an improved P and O (P and Ob) method has been put forward in this paper by using the Atken interpolation algorithm. To validate the correctness and performance of the proposed method, simulation and experimental study have been implemented. Simulation models of classical P and Oa method and improved P and Ob method have been established by MATLAB/Simulink to analyze each technique under varying solar irradiation and temperature. The experimental results show that the tracking efficiency of P and Ob method is an average of 93% compared to 72% for P and Oa method, this conclusion basically agree with the simulation study. Finally, we proposed the applicable conditions and scope of these MPPT methods in the practical application

  13. 2D Spatial Frequency Considerations in Comparing 1D Power Spectral Density Measurements

    International Nuclear Information System (INIS)

    Takacs, P.Z.; Barber, S.; Church, E.L.; Kaznatcheev, K.; McKinney, W.R.; Yashchuk, V.Y.

    2010-01-01

    The frequency footprint of ID and 2D profiling instruments needs to be carefully considered in comparing ID surface roughness spectrum measurements made by different instruments. Contributions from orthogonal direction frequency components can not be neglected. The use of optical profiling instruments is ubiquitous in the measurement of the roughness of optical surfaces. Their ease-of-use and non-contact measurement method found widespread use in the optics industry for measuring the quality of delicate optical surfaces. Computerized digital data acquisition with these instruments allowed for quick and easy calculation of surface roughness statistics, such as root-mean-square (RMS) roughness. The computing power of the desktop computer allowed for the rapid conversion of spatial domain data into the frequency domain, enabling the application of sophisticated signal processing techniques to be applied to the analysis of surface roughness, the most powerful of which is the power spectral density (PSP) function. Application of the PSD function to surface statistics introduced the concept of 'bandwidth-limited' roughness, where the value of the RMS roughness depends critically upon the spatial frequency response of the instrument. Different instruments with different spatial frequency response characteristics give different answers when measuring the same surface.

  14. Space Fission Reactor Structural Materials: Choices Past, Present and Future

    International Nuclear Information System (INIS)

    Busby, Jeremy T.; Leonard, Keith J.

    2007-01-01

    Nuclear powered spacecraft will enable missions well beyond the capabilities of current chemical, radioisotope thermal generator and solar technologies. The use of fission reactors for space applications has been considered for over 50 years, although, structural material performance has often limited the potential performance of space reactors. Space fission reactors are an extremely harsh environment for structural materials with high temperatures, high neutron fields, potential contact with liquid metals, and the need for up to 15-20 year reliability with no inspection or preventative maintenance. Many different materials have been proposed as structural materials. While all materials meet many of the requirements for space reactor service, none satisfy all of them. However, continued development and testing may resolve these issues and provide qualified materials for space fission reactors.

  15. Micro fission chamber for the ITER neutron monitor

    International Nuclear Information System (INIS)

    Yamauchi, Michinori; Nishitani, Takeo; Ochiai, Kentaro; Ebisawa, Katsuyuki

    2004-01-01

    This paper describes the design and the fabrication of a prototype micro-fission chamber and test results under ITER relevant conditions including wide neutron spectrum and intense gamma-rays, and the performance as a ITER power monitor is discussed. A micro-fission chamber with 12 mg UO 2 and a dummy chamber without uranium were designed and fabricated for the in-vessel neutron flux monitoring of ITER. The measurement ability was tested with the FNS facility for 14 MeV neutrons and the 60 Co gamma-ray irradiation facility at JAERI-Takasaki. Employing the Campbelling mode in the electronics, the ITER requirement for the temporal resolution was satisfied. The excellent linearity of the detector output versus the neutron flux was confirmed in the temperature range from 20degC to 250degC. As a result, it was concluded that the developed micro-fission chamber is applicable for ITER. (author)

  16. Thorium-uranium fission radiography

    Science.gov (United States)

    Haines, E. L.; Weiss, J. R.; Burnett, D. S.; Woolum, D. S.

    1976-01-01

    Results are described for studies designed to develop routine methods for in-situ measurement of the abundance of Th and U on a microscale in heterogeneous samples, especially rocks, using the secondary high-energy neutron flux developed when the 650 MeV proton beam of an accelerator is stopped in a 42 x 42 cm diam Cu cylinder. Irradiations were performed at three different locations in a rabbit tube in the beam stop area, and thick metal foils of Bi, Th, and natural U as well as polished silicate glasses of known U and Th contents were used as targets and were placed in contact with mica which served as a fission track detector. In many cases both bare and Cd-covered detectors were exposed. The exposed mica samples were etched in 48% HF and the fission tracks counted by conventional transmitted light microscopy. Relative fission cross sections are examined, along with absolute Th track production rates, interaction tracks, and a comparison of measured and calculated fission rates. The practicality of fast neutron radiography revealed by experiments to data is discussed primarily for Th/U measurements, and mixtures of other fissionable nuclei are briefly considered.

  17. Updated comparison of economics of fusion reactors with advanced fission reactors

    International Nuclear Information System (INIS)

    Delene, J.G.

    1990-01-01

    The projected cost of electricity (COE) for fusion is compared with that from current and advanced nuclear fission and coal-fired plants. Fusion cost models were adjusted for consistency with advanced fission plants and the calculational methodology and cost factors follow guidelines recommended for cost comparisons of advanced fission reactors. The results show COEs of about 59--74 mills/kWh for the fusion designs considered. In comparison, COEs for future fission reactors are estimated to be in the 43--54 mills/kWh range with coal-fired plant COEs of about 53--69 mills/kWh ($2--3/GJ coal). The principal cost driver for the fusion plants relative to fission plants is the fusion island cost. Although the estimated COEs for fusion are greater than those for fission or coal, the costs are not so high as to preclude fusion's competitiveness as a safe and environmentally sound alternative

  18. Study of fission dynamics with the three-dimensional Langevin equations

    Energy Technology Data Exchange (ETDEWEB)

    Eslamizadeh, H. [Persian Gulf University, Department of Physics, Bushehr (Iran, Islamic Republic of)

    2011-11-15

    The dynamics of fission has been studied by solving one- and three-dimensional Langevin equations with dissipation generated through the chaos weighted wall and window friction formula. The average prescission neutron multiplicities, fission probabilities and the mean fission times have been calculated in a broad range of the excitation energy for compound nuclei {sup 210}Po and {sup 224}Th formed in the fusion-fission reactions {sup 4}He+{sup 206}Pb, {sup 16}O+{sup 208}Pb and results compared with the experimental data. The analysis of the results shows that the average prescission neutron multiplicities, fission probabilities and the mean fission times calculated by one- and three-dimensional Langevin equations are different from each other, and also the results obtained based on three-dimensional Langevin equations are in better agreement with the experimental data. (orig.)

  19. Recent improvements in the calculation of prompt fission neutron spectra: Preliminary results

    International Nuclear Information System (INIS)

    Madland, D.G.; LaBauve, R.J.; Nix, J.R.

    1989-01-01

    We consider three topics in the refinement and improvement of our original calculations of prompt fission neutron spectra. These are an improved calculation of the prompt fission neutron spectrum N(E) from the spontaneous fission of 252 Cf, a complete calculation of the prompt fission neutron spectrum matrix N(E,E n ) from the neutron-induced fission of 235 U, at incident neutron energies ranging from 0 to 15 MeV, and an assessment of the scission neutron component of the prompt fission neutron spectrum. Preliminary results will be presented and compared with experimental measurements and an evaluation. A suggestion is made for new integral cross section measurements. (author). 45 refs, 12 figs, 1 tab

  20. Energy production using fission fragment rockets

    International Nuclear Information System (INIS)

    Chapline, G.; Matsuda, Y.

    1991-08-01

    Fission fragment rockets are nuclear reactors with a core consisting of thin fibers in a vacuum, and which use magnetic fields to extract the fission fragments from the reactor core. As an alternative to ordinary nuclear reactors, fission fragment rockets would have the following advantages: Approximately twice as efficient if one can directly convert the fission fragment energy into electricity; by reducing the buildup of a fission fragment inventory in the reactor one could avoid a Chernobyl type disaster; and collecting the fission fragments outside the reactor could simplify the waste disposal problem. 6 refs., 4 figs., 2 tabs

  1. Contribution to the study of nuclear fission

    International Nuclear Information System (INIS)

    Serot, O.

    2009-09-01

    The author proposes an overview of his research activity during the past fifteen years and more particularly that dealing with nuclear fission. The first part reports works on nucleus physics at the scission via the investigation of ternary fission (experimental procedure, influence of fission modes, influence of resonance spin, influence of excitation energy of the fissioning nucleus, emission probabilities, energy spectra of ternary alphas and tritons, emission mechanism). The second part reports measurements and assessments of neutron-induced fission cross sections. The third part reports the investigation of some properties of fission products (efficiencies, branching ratios of the main delayed neutron precursors)

  2. A high speed low power low offset dynamic comparator used in SHA-less pipelined ADC

    Science.gov (United States)

    Shubin, Liu; Zhangming, Zhu; Yintang, Yang; Lianxi, Liu

    2014-05-01

    A novel fully differential high speed high resolution low offset CMOS dynamic comparator has been implemented in the SMIC 0.18 μm process used for a sample-and-hold amplifier (SHA)-less pipelined analog-to-digital converters (ADC). Based on the analysis and optimization between delay time and offset, an enhanced reset architecture with transmission gate was introduced to speed up the comparison and reset procedure. Four inputs with two cross coupled differential pairs, reconstituted bias circuit for tail current transistor and common centroid layouts make the comparator more robust against mismatch and process variations. The simulation results demonstrate that the proposed design achieves 1 mV sensitivity at 2.2 GHz sampling rate with a power consumption of 510 μW, while the mean offset voltage is equal to 10.244 mV.

  3. An Evaluation of a Fission Product Inventory for CANDU Fuels

    International Nuclear Information System (INIS)

    Jung, Jong Yeob; Park, Joo Hwan

    2007-01-01

    Fission products are released by two processes when a single channel accident occurs. One is a 'prompt release' and the other is a 'delayed release'. Prompt release assumes that the gap inventory of the fuel elements is released by a fuel element failure at the time of an accident. Delayed release assumes that the inventories within the grain or at the grain boundary are released after a accident due to a diffusion through grains, an oxidation of the fuel and an interaction between the fuel and the Zircaloy sheath. Therefore, the calculation of a fission product inventory and its distribution in a fuel during a normal operating is the starting point for the assessment of a fission product release for single channel accidents. In this report, the fission product inventories and their distributions within s fuel under a normal operating condition are evaluated for three types of CANDU fuels such as the 37 element fuel, CANFLEX-NU and CANFLEX-RU fuel bundles in the 'limiting channel'. To accomplish the above mentioned purposes, the basic power histories for each type of CANDU fuel were produced and the fission product inventories were calculated by using the ELESTRES code

  4. Nuclear fission and neutron-induced fission cross-sections

    CERN Document Server

    James, G D; Michaudon, A; Michaudon, A; Cierjacks, S W; Chrien, R E

    2013-01-01

    Nuclear Fission and Neutron-Induced Fission Cross-Sections is the first volume in a series on Neutron Physics and Nuclear Data in Science and Technology. This volume serves the purpose of providing a thorough description of the many facets of neutron physics in different fields of nuclear applications. This book also attempts to bridge the communication gap between experts involved in the experimental and theoretical studies of nuclear properties and those involved in the technological applications of nuclear data. This publication will be invaluable to those interested in studying nuclear fis

  5. Development of a tool for comparing different nuclear power reactor technologies: the Mexican choice

    International Nuclear Information System (INIS)

    Martin-del-Campo, C.; Francois, J.L.; Reyes, R.

    2007-01-01

    This paper describes a methodology which has allowed us to make a comparative assessment of nuclear power reactor options. The methodology was divided in 3 steps. The first step consists in searching of common indicators to be compared. A total of twenty indicators were considered and grouped in 3 main criteria. The second step is to obtain the values of all the indicators for each of the reactor technologies being compared. The third step is to utilize an aggregation method to integrate all the indicators in an overall qualification. Fuzzy Logic was selected as multi criteria aggregation method because it copes with imprecisely defined data; it can model non-linear functions of arbitrary complexity; and it is able to build on top of the experience of experts. The Fuzzy Logic inference system was built using the MATLAB toolbox; 3 fuzzy sets were described for each entry variable (Indicator) and 5 fuzzy sets for the output variable (Qualification). Both, the set of membership function and the set of rules were defined in combination. The methodology is simple but at the same time is powerful; it allows the use of all the indicators with their own magnitudes and units. Five reactors were compared: the Advanced Boiling Water Reactor (ABWR), the Economic Simplified Boiling Water Reactor (ESBWR), the Evolutionary Pressurized water Reactor (EPR), the Advanced Pressurized water reactor 1000 (AP1000) and the Pebbled Bed Modular Reactor (PBMR). Preliminary results were obtained using non official data obtained from public information. The qualifications of the reactors appear to be quite near. This work should be improved by taking into account which indicator is important and grading the indicators according to the situation in Mexico. (authors)

  6. Comparative Evaluation of Biomass Power Generation Systems in China Using Hybrid Life Cycle Inventory Analysis

    Science.gov (United States)

    Liu, Huacai; Yin, Xiuli; Wu, Chuangzhi

    2014-01-01

    There has been a rapid growth in using agricultural residues as an energy source to generate electricity in China. Biomass power generation (BPG) systems may vary significantly in technology, scale, and feedstock and consequently in their performances. A comparative evaluation of five typical BPG systems has been conducted in this study through a hybrid life cycle inventory (LCI) approach. Results show that requirements of fossil energy savings, and greenhouse gas (GHG) emission reductions, as well as emission reductions of SO2 and NOx, can be best met by the BPG systems. The cofiring systems were found to behave better than the biomass-only fired system and the biomass gasification systems in terms of energy savings and GHG emission reductions. Comparing with results of conventional process-base LCI, an important aspect to note is the significant contribution of infrastructure, equipment, and maintenance of the plant, which require the input of various types of materials, fuels, services, and the consequent GHG emissions. The results demonstrate characteristics and differences of BPG systems and help identify critical opportunities for biomass power development in China. PMID:25383383

  7. Comparative Study of Maximum Power Point Tracking Techniques for Photovoltaic Systems

    Directory of Open Access Journals (Sweden)

    Fernando Lessa Tofoli

    2015-01-01

    Full Text Available The generation of electricity from photovoltaic (PV arrays has been increasingly considered as a prominent alternative to fossil fuels. However, the conversion efficiency is typically low and the initial cost is still appreciable. A required feature of a PV system is the ability to track the maximum power point (MPP of the PV array. Besides, MPP tracking (MPPT is desirable in both grid-connected and stand-alone photovoltaic systems because the solar irradiance and temperature change throughout the day, as well as along seasons and geographical conditions, also leading to the modification of the I×V (current versus voltage and P×V (power versus voltage curves of the PV module. MPPT is also justified by the relatively high cost of the energy generated by PV systems if compared with other sources. Since there are various MPPT approaches available in the literature, this work presents a comparative study among four popular techniques, which are the fixed duty cycle method, constant voltage (CV, perturb and observe (P&O, and incremental conductance (IC. It considers different operational climatic conditions (i.e., irradiance and temperature, since the MPP is nonlinear with the environment status. PSIM software is used to validate the assumptions, while relevant results are discussed in detail.

  8. A comparative exergoeconomic analysis of different ORC configurations for binary geothermal power plants

    International Nuclear Information System (INIS)

    Zare, V.

    2015-01-01

    Highlights: • Three ORC configurations for geothermal power plants are compared exergoeconomically. • ORC with internal heat exchanger has the best thermodynamic performance. • Simple ORC has the best economic performance. - Abstract: The main goal of this research is to investigate and compare the performance of three configurations of organic Rankine cycle (ORC) for binary geothermal power plants from the viewpoints of both thermodynamics and economics. The considered configurations are: Simple organic Rankine cycle (S-ORC), Regenerative organic Rankine cycle (R-ORC) and organic Rankine cycle with Internal Heat Exchanger (ORC-IHE). To assess the cycles’ performances, thermodynamic and exergoeconomic models are developed and a parametric study is carried out prior to the optimization with respect to the total product cost minimization, as the objective function. Also, a profitability evaluation of the investigated systems is performed based on the total capital investment and payback period. The results indicate that, from the thermodynamic point of view (first and second law efficiencies), the ORC-IHE has superior performance while from the economic viewpoint the S-ORC is the best case among the considered cycles.

  9. Comparative Evaluation of Biomass Power Generation Systems in China Using Hybrid Life Cycle Inventory Analysis

    Directory of Open Access Journals (Sweden)

    Huacai Liu

    2014-01-01

    Full Text Available There has been a rapid growth in using agricultural residues as an energy source to generate electricity in China. Biomass power generation (BPG systems may vary significantly in technology, scale, and feedstock and consequently in their performances. A comparative evaluation of five typical BPG systems has been conducted in this study through a hybrid life cycle inventory (LCI approach. Results show that requirements of fossil energy savings, and greenhouse gas (GHG emission reductions, as well as emission reductions of SO2 and NOx, can be best met by the BPG systems. The cofiring systems were found to behave better than the biomass-only fired system and the biomass gasification systems in terms of energy savings and GHG emission reductions. Comparing with results of conventional process-base LCI, an important aspect to note is the significant contribution of infrastructure, equipment, and maintenance of the plant, which require the input of various types of materials, fuels, services, and the consequent GHG emissions. The results demonstrate characteristics and differences of BPG systems and help identify critical opportunities for biomass power development in China.

  10. Nuclear power

    International Nuclear Information System (INIS)

    Abd Khalik Wood

    2003-01-01

    This chapter discuss on nuclear power and its advantages. The concept of nucleus fission, fusion, electric generation are discussed in this chapter. Nuclear power has big potential to become alternative energy to substitute current conventional energy from coal, oil and gas

  11. The fission-track analysis: An alternative technique for provenance studies of prehistoric obsidian artefacts

    CERN Document Server

    Bellot-Gurlet, L; Dorighel, O; Oddone, M; Poupeau, G; Yegingil, Z

    1999-01-01

    Comparison of fission-track parameters - age and track densities - is an alternative tool for correlating obsidian artefacts with their potential natural sources. This method was applied by different fission-track groups in various regions and results were compared with those obtained using the more popular provenance identification techniques based on chemical composition studies. Hundreds of analyses prove that fission-track dating is a complementary technique which turns out to be very useful, specially when the chemical composition does not fully discriminate different sources. Archaeologically significant results were obtained applying the fission-track analysis in various regions of earth.

  12. The fission-track analysis: An alternative technique for provenance studies of prehistoric obsidian artefacts

    International Nuclear Information System (INIS)

    Bellot-Gurlet, L.; Bigazzi, G.; Dorighel, O.; Oddone, M.; Poupeau, G.; Yegingil, Z.

    1999-01-01

    Comparison of fission-track parameters - age and track densities - is an alternative tool for correlating obsidian artefacts with their potential natural sources. This method was applied by different fission-track groups in various regions and results were compared with those obtained using the more popular provenance identification techniques based on chemical composition studies. Hundreds of analyses prove that fission-track dating is a complementary technique which turns out to be very useful, specially when the chemical composition does not fully discriminate different sources. Archaeologically significant results were obtained applying the fission-track analysis in various regions of earth

  13. Fission fragment simulation of fusion neutron radiation effects on bulk mechanical properties

    International Nuclear Information System (INIS)

    Van Konynenburg, R.A.; Mitchell, J.B.; Guinan, M.W.; Stuart, R.N.; Borg, R.J.

    1976-01-01

    This research demonstrates the feasibility of using homogeneously-generated fission fragments to simulate high-fluence fusion neutron damage in niobium tensile specimens. This technique makes it possible to measure radiation effects on bulk mechanical properties at high damage states, using conveniently short irradiation times. The primary knock-on spectrum for a fusion reactor is very similar to that produced by fission fragments, and nearly the same ratio of gas atoms to displaced atoms is produced in niobium. The damage from fission fragments is compared to that from fusion neutrons and fission reactor neutrons in terms of experimentally measured yield strength increase, transmission electron microscopy (TEM) observations, and calculated damage energies

  14. Fusion-Fission hybrid reactors and nonproliferation

    International Nuclear Information System (INIS)

    Greenspan, E.

    1984-09-01

    New options for the development of the nuclear energy economy which might become available by a successful development of fusion-breeders or fusion-fission hybrid power reactors, identified and their nonproliferative attributes are discussed. The more promising proliferation-resistance ettributes identified include: (1) Justification for a significant delay in the initiation of fuel processing, (2) Denaturing the plutonium with 238 Pu before its use in power reactors of any kind, and (3) Making practical the development of denatured uranium fuel cycles and, in particular, denaturing the uranium with 232 U. Fuel resource utilization, time-table and economic considerations associated with the use of fusion-breeders are also discussed. It is concluded that hybrid reactors may enable developing a nuclear energy economy which is more proliferation resistant than possible otherwise, whileat the same time, assuring high utilization of t he uranium and thorium resources in an economically acceptable way. (author)

  15. Contribution to the study of the influences of the excitation energy on the characteristics of the fission process

    International Nuclear Information System (INIS)

    Wagemans, C.

    1979-01-01

    Neutron induced and spontaneous fission with neutron energies from 10 -2 to 2.10 5 eV have been studied. Thermal neutron induced fission measurements in Pa 231 , Th 232 , Np 237 , U 233 , U 235 , Pu 239 and Pu 241 are reported. Energy and mass distributions of heavy fission fragments due to the spontaneous fission of Pu 240 are compared to the results obtained by thermal neutron fission of Pu 239 ; the events observed with U 236 , Pu 240 , Pa 232 and Np 238 are explained by the Bohr theory of fission channels. Ternary fission phenomena of U 233 , U 235 , Pu 239 , Pa 231 and Np 237 induced by thermal neutrons are explained and compared to models of Carjan and Feather. (MDC)

  16. Differences in muscle mechanical properties between elite power and endurance athletes: a comparative study.

    Science.gov (United States)

    Loturco, Irineu; Gil, Saulo; Laurino, Cristiano Frota de Souza; Roschel, Hamilton; Kobal, Ronaldo; Cal Abad, Cesar C; Nakamura, Fabio Y

    2015-06-01

    The aim of this study was to compare muscle mechanical properties (using tensiomyography-TMG) and jumping performance of endurance and power athletes and to quantify the associations between TMG parameters and jumping performance indices. Forty-one high-level track and field athletes from power (n = 22; mean ± SD age, height, and weight were 27.2 ± 3.6 years; 180.2 ± 5.4 cm; and 79.4 ± 8.6 kg, respectively) and endurance (endurance runners and triathletes; n = 19; mean ± SD age, height, and weight were 27.1 ± 6.9 years; 169.6 ± 9.8 cm; 62.2 ± 13.1 kg, respectively) specialties had the mechanical properties of their rectus femoris (RF) and biceps femoris (BF) assessed by TMG. Muscle displacement (Dm), contraction time (Tc), and delay time (Td) were retained for analyses. Furthermore, they performed squat jumps (SJs), countermovement jumps (CMJs), and drop jumps to assess reactive strength index (RSI), using a contact platform. Comparisons between groups were performed using differences based on magnitudes, and associations were quantified by the Spearman's ρ correlation. Power athletes showed almost certain higher performance in all jumping performance indices when compared with endurance athletes (SJ = 44.9 ± 4.1 vs. 30.7 ± 6.8 cm; CMJ = 48.9 ± 4.5 vs. 33.6 ± 7.2 cm; RSI = 2.19 ± 0.58 vs. 0.84 ± 0.39, for power and endurance athletes, mean ± SD, respectively; 00/00/100, almost certain, p ≤ 0.05), along with better contractile indices reflected by lower Dm, Tc, and Td (Tc BF = 14.3 ± 2.3 vs. 19.4 ± 3.3 milliseconds; Dm BF = 1.67 ± 1.05 vs. 4.23 ± 1.75 mm; Td BF = 16.8 ± 1.6 vs. 19.6 ± 1.3 milliseconds; Tc RF = 18.3 ± 2.8 vs. 22.9 ± 4.0 milliseconds; Dm RF = 4.98 ± 3.71 vs. 8.88 ± 3.45 mm; Td RF = 17.5 ± 1.0 vs. 20.9 ± 1.6 milliseconds, for power and endurance athletes, mean ± SD, respectively; 00/00/100, almost certain, p ≤ 0.05). Moderate correlations (Spearman's ρ between -0.61 and -0.72) were found between TMG and jumping

  17. Singlet Fission in Rubrene Derivatives: Impact of Molecular Packing

    KAUST Repository

    Sutton, Christopher

    2017-03-13

    We examine the properties of six recently synthesized rubrene derivatives (with substitutions on the side phenyl rings) that show vastly different crystal structures. In order to understand how packing in the solid state affects the excited states and couplings relevant for singlet fission, the lowest excited singlet (S), triplet (T), multiexciton (TT), and charge-transfer (CT) states of the rubrene derivatives are compared to known singlet fission materials [tetracene, pentacene, 5,12-diphenyltetracene (DPT), and rubrene itself]. While a small difference of less than 0.2 eV is calculated for the S and TT energies, a range of 0.50 to 1.2 eV in the CT energies and nearly 3 orders of magnitude in the electronic couplings are computed for the rubrene derivatives in their crystalline packings, which strongly affects the role of the CT state in facilitating SF. To rationalize experimental observations of singlet fission occurring in amorphous phases of rubrene, DPT, and tetracene, we use molecular dynamics (MD) simulations to assess the impact of molecular packing and orientations and to gain a better understanding of the parameters that control singlet fission in amorphous films compared to crystalline packings. The MD simulations point to a crystalline-like packing for thin films of tetracene; on the other hand, DPT, rubrene, and the rubrene derivatives all show various degrees of disorder with a number of sites that have larger electronic couplings than in the crystal, which can facilitate singlet fission in such thin films. Our analysis underlines the potential of these materials as promising candidates for singlet fission and helps understand how various structural motifs affect the critical parameters that control the ability of a system to undergo singlet fission.

  18. Reliability of the electric power supply in the safety apparatus of nuclear power plants: a comparative analysis

    International Nuclear Information System (INIS)

    Cruz, L.A.

    1992-01-01

    This paper discusses the risk of total loss of electric power supply to the Class 1E system. Two alternatives are focused: a system with two off-site and two onsite power supplies emergency power supply, as recommended by the American Regulations, and a system with only one off-site and four on-site power supplies, applicable when two off-site are not available. To allow the fact that the equipment can be repaired, the method proper involves use of the Markov model, with which one can find, for each configuration of the system, the change over time of the probability of a simultaneous failure of all power sources. The sensitivity of each parameter is studied in each case and, on the basis of the results of the study, the author conclude that the system with two off-site power supplies is preferable in all alternatives analysed, although the system with one off-site power supply can be adopted with high reliability diesel-generators. (author)

  19. Fission-fragment and neutron data traced back to the macroscopic and microscopic properties of the fissioning systems

    Directory of Open Access Journals (Sweden)

    Schmidt K.-H.

    2010-10-01

    Full Text Available A new model description of fission-fragment yields and prompt neutron emission is developed. The yields of the different fission channels and their properties are attributed to the number of relevant states above the potential-energy landscape on the fission path at the moment of dynamical freeze-out, which is specific to the collective coordinate considered. The model combines well established ideas with novel concepts. The separability principle of macroscopic properties of the compound nucleus and microscopic properties of the fragments strongly reduces the number of model parameters and assures a high predictive power. The recently discovered energy-sorting mechanism in superfluid nuclear dynamics determines the sharing of intrinsic excitation energy at scission and the enhancement of even-odd structure in asymmetric splits.

  20. Comparative Study on Cyber Securities between Power Reactor and Research Reactor with Bayesian Update

    International Nuclear Information System (INIS)

    Shin, Jinsoo; Heo, Gyunyoung; Son, Han Seong

    2016-01-01

    The Stuxnet has shown that nuclear facilities are no more safe from cyber-attack. Due to practical experiences and concerns on increasing of digital system application, cyber security has become the important issue in nuclear industry. Korea Institute of Nuclear Nonproliferation and control (KINAC) published a regulatory standard (KINAC/RS-015) to establish cyber security framework for nuclear facilities. However, it is difficult to research about cyber security. It is hard to quantify cyber-attack which has malicious activity which is different from existing design basis accidents (DBAs). We previously proposed a methodology on development of a cyber security risk model with BBN. However, the methodology had a limitation in which the input data as prior information was solely on expert opinions. In this study, we propose a cyber security risk model for instrumentation and control (I and C) system of nuclear facilities with some equation for quantification by using Bayesian Belief Network (BBN) in order to overcome the limitation of previous research. The proposed model has been used for comparative study on cyber securities between large-sized nuclear power plants (NPPs) and small-sized Research Reactors (RR). In this study, we proposed the cyber security risk evaluation model with BBN. It includes I and C architecture, which is a target system of cyber-attack, malicious activity, which causes cyber-attack from attacker, and mitigation measure, which mitigates the cyber-attack risk. Likelihood and consequence as prior information are evaluated by considering characteristics of I and C architecture and malicious activity. The BBN model provides posterior information with Bayesian update by adding any of assumed cyber-attack scenarios as evidence. Cyber security risk for nuclear facilities is analyzed by comparing between prior information and posterior information of each node. In this study, we conducted comparative study on cyber securities between power reactor